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               How To Build A 347 To 355 Inch Stroker 302

                       version 1.03, 09/02/1998

                           by Dave Williams
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---Why?

 Why would you want to stroke your 289, 302, or 5.0?  Maybe you just
want to; no problem with that.  Or you could be an autocrosser or
trackie who wants to avoid the weight penalty of going to a 351
Windsor.  Of you might live in a place where smog inspections make
swapping motors impractical.  Whatever your reason, here's what has
to be done.


---347 vs. 355:

 Most of the magazine motors you see are 347 cubic inches.  They use
5.3 or 5.4" aftermarket rods and expensive pistons with a nonstandard
pin height.  The trick to a long rod 347 is it will require much less
crankshaft and block clearancing than most other combinations.  Time
is money, particularly shop time.  If you're clearancing the parts at
home it doesn't make a whole lot of difference.

 One possible combination I haven't actually done is to use the 2.3 HSC
(Ford Tempo four) rods, which are 5.45" long, and modified pistons.  The
HSC rods aren't that easy to come by, but if you can find some, most of
the information below will apply to that combination.

 I'll be showing you how to build a 355 using Pinto rods and Chevy
pistons.  These parts are inexpensive, strong, and available just about
anywhere.  Many of the early strokers used this setup.  Big shops have
moved away from it because it's labor-intensive, and they can build a
347 for the same price, but less work.

 The blower and nitrous guys don't seem to have any problem with the  
Cleveland cranks.  The block appears to be the weak point.

 Now, oddly enough, lots more people ask about 331 size motors than
347 or 355 size motors.  I'm not exactly sure why.  Anyway, there is
no inexpensive route to build a 331; there is no drop-in junkyard
parts combo to work with minor massaging like the bigger motors.
331s have been built using severely destroked Cleveland cranks, with
stroked 302 cranks and custom bits, and probably other ways.  But
none of them are cheap, and a few of them are probably borderline on
strength even in very mild tune.  Yet you see lots of 331s in the
magazines.  That's because it's a nice fit within the block, requires
little or no clearancing, and the cost is zero - assuming you're
already buying an forged aftermarket crank, aftermarket rods, and
custom built forged pistons, "parts is parts".


    Building A Big 302:

---Ingredients:

(1) 289, 302, or 5.0 block
        There are various differences in the blocks, but for our
        purposes the only meaningful one piece or two piece rear
        main seal.  The 289, 302, and 5.0 all have the same cylinder
        depth (5-1/8" over a sample of 8 blocks) despite what you
        may have read in the magazines.  The strongest *looking*
        blocks are the 289s, C8 or C9 302s, or E7 5.0s.  The D9
        blocks are thin in several places and the casting quality
        often doesn't look so good.  
        
(1) 351 Cleveland crankshaft
        This crank is identified with a large 4M casting mark.
        There are at least two variants.  One has the oil holes
        drilled differently than the other.  Unfortunately, I'm not
        *exactly* sure how to tell one from the other.  My present
        theory is that the ones with the flywheel bolt holes drilled
        completely through the rear flange are the ones to avoid;
        you want the ones with the blind-tapped holes.  Either type
        of crank will work, but the blind-tapped crank's oil holes
        are positioned better for our purposes.

(8) 2300 Ford (Pinto) rods
        These rods usually have a D4AE forging number, though you
        can sometimes find others.  The early rods have an oil
        squirt hole on the side.  Later rods have the bump, but no
        hole.  I prefer the ones with the oil hole, "just because".
        The 2300 rods are longer, heavier, and stronger than the
        stock 5.0 rods; don't be concerned because they're from a
        four cylinder

(8) pair 2300 rod bearings
        These bearings used to be available in the usual .010, .020
        undersizes.  As of early '98 all major vendors seem to be
        changing over to *metric* undersizes.  You will probably use
        standard size bearings, but keep an eye out if you have to
        have the crank cut to undersize.

(8) 1.25 or 1.26" pin height pistons
        The usual piston is the Keith Black KB112 flat top with
        a 1.261" pin height.  It is for a Chevy 350 with stock
        3.48" stroke and 6" rods.  The KBs run about $225-$250 a
        set, less than half the price of an equivalent forged
        piston.  Ohio Cast also makes an acceptable piston,
        available from various sources (see any issue of Circle
        Track for ads).  It's cast, but popular among the local
        dirt tracker types and seems adequately strong.  I've
        used them in other applications.  The price is right -
        $99 to $129.  I've also seen Manley forgings on sale for
        $325 or so, significantly cheaper than the Ross or JE parts.

        Some pistons will be specified as "left hand" or "right
        hand"; *sets* intended for a Chevy will have four of
        each.  You want eight "left hand" pistons for a Ford
        application.  That's "left hand exhaust", not engine
        side.


---Process:

(A) Crankshaft:
        The first thing you need to do is profile the counterweights.
        The Pinto rods are half an inch shorter than the Cleveland
        rods, so around half an inch needs to come off the crank in
        various spots.

        You will need to know how much metal to remove, and where.
        The simplest thing to do is take a spare Cleveland rod and
        any small block or most six or four cylinder Chevy rod,
        cut each in half, and weld or epoxy the Cleveland big end
        to the Chevy small end, 5.205" center to center.  Use
        Cleveland main bearings, or just wrap the journal in tape
        to build it up to a snug fit to the inside of the rod.
        You don't really need the cap or bolts.  Now trim down a
        piece of wooden dowel or pipe, or build a piece up with
        tape, to act as a temporary wrist pin.  You now have a
        counterweight clearancing gage.  Put the big end on the
        crank and swing the rod and piston around until they hit the
        counterweight.  Mark that spot with a grease pencil or
        felt tip.  Swing it the other way until it hits the weight
        on the other side.  Mark that.

        Now you'll need to grind for a while.  An 8" body grinder
        will work, but the smaller 4 or 4-1/2" grinders are much
        more convenient.  $60 or so for one at Wal-Mart if you
        don't have one.  Use the coarsest discs you can find, and
        buy several spares.  I can usually find 16 grit.  You will
        now remove several *pounds* of metal from the crank in the
        form of dust and teeny sparklies.  It is loud, messy, and
        tiresome.  Figure most of a day for this.  I recommend
        goggles and some sort of breath filter, and one of those
        cheap disposable plastic ponchos, or even a plastic garbage
        bag with head and arm holes to keep the grunge off.  There
        aren't really any safety issues here, but you will be
        amazed at how nasty cast iron dust can be.

        Grind until you have about .060" clearance between the
        bottom of the piston and the counterweight at all points.
        The thickness of an ordinary 1/4" wide zip tie is about
        right.  Leave the edges of the counterweights square.  You
        want to leave as much metal on the counterweights as you
        can, to prevent great expenditures in heavy metal later.

        Speaking of heavy metal, removing extra weight from the rod
        throws will help the situation.  The rod throws are mostly
        square.  You can thin and curve them quite a bit without
        losing any strength.  If you're uncertain, buy David
        Vizard's "How To Build Small Block Chevy Crankshafts, Pistons,
        and Rods" and take a look at the pictures.  There's a lot
        of metal that can come off to your benefit, and now's the
        time.

        Now you're ready to go to the crank shop.

        The crank must be cut down from 2.75" to 2.25" on the main
        journals and from 2.311" to 2.04" on the rod journals.  This
        is a *lot* of metal.  It will cost a lot of money depending
        on what sort of deal you can work out with the engine shop.
        It will take six to eight hours depending on what sort of
        grinder the shop has, and the grit of the wheel.  Changing
        to a coarser wheel will remove metal faster, but changing
        wheels is awkward and time-consuming, so most shops don't
        like to do it.

        If the shop hasn't done much stroking work that involves 
        removing such large (1/4 and 1/2 inch) amounts of metal, they
        will need to watch out for side wear on the grinding wheel.
        As the wheel cuts more deeply into the crank to reduce the
        journal diameter it will wear on the sides as well as the
        end.  This will give tapered sides to the journals, which
        will make it impossible to install the connecting rods later.

        This is the time to adjust the stroke if you want.  You can
        keep the full 3.5" stroke with the Pinto rods and KB
        pistons.  This results in .003 to .005 of the piston
        sticking out of the top of the block.  That's just fine,
        some stock 5.0s stick out more than that.

        Tell them *not* to chamfer the oil holes.  You'll do that
        yourself later.  Chamfering the oil holes is automatic
        reflex in many shops; you might use a bright yellow marker
        and write it on the counterweights.  It won't be a disaster
        if they do, but it can cause oil bleed troubles if your
        oil holes shifted much during the grinding.

        Once you have the journals cut to the right diameter, the
        center main needs to be widened.  The 351C, oddly, has a
        narrower thrust bearing than the 302.  Then the oil slinger
        and rear main need to be cut down slightly from 351C size
        to 302 two-piece or 5.0 one-piece seal size.  Now look at
        the front counterweight.  See the raised circular area?
        That needs to be ground off to clear the oil pump drive
        rod.  You can do the work with the angle grinder before
        you take it to the crank shop, or you can have the crank
        guy do it now.

        The next step at the crank shop is the snout ring.  Ahead
        of the front main you'll see a 1/4" wide or so ring, smaller
        in diameter than the main.  This needs to come off.  Most
        shops simply grind it flush with the front of the main, but
        the distance from the front of the center main bearing to
        the end of the front main is critical, since that's what
        lines up the lower timing sprocket with the upper timing
        sprocket.  Most shops don't have any tools suitable for
        making an accurate measurement for a distance this size.
        With a little ingenuity you can make a caliper out of some
        hardware store steel; make one end adjustable with a bolt.
        Set the caliper to a real 302 crank, then use it as a go/
        no go guage.  Practically, if you're within .005 or so you
        should be okay.

        The snout itself needs to be shortened approximately 3/8
        of an inch, otherwise it will stick out past the 302 harmonic
        balancer and the bolt won't hold it tight.  The exact amount
        to be shortened may vary; you want to the length from the
        face of the front journal, which you just cut to length in the
        step above, to be the same as a 302 crank, about 2.95".  I
        don't know that all 351Cs are the same.  Anyway, as long as
        you're .030-.060" shorter than the depth of the balancer and
        lower sprocket you're okay.  You can use a lathe to shorten
        the snout, but an angle grinder or abrasive cutoff wheel will
        work just fine, though it won't be as pretty.  Make sure you
        radius or chamfer the snout to make it easier to install the
        harmonic balancer.

        The final step at the crank shop is to turn the snout OD
        down to Windsor size in the sprocket area.  Most Clevelands
        seem to be a few thousandths larger than the Windsors,
        making installation and removal of the lower sprocket a
        problem.

        Expect to pay anywhere from $200 to $600 for these services.

        Next you need an extra keyway on the snout.  The Cleveland's
        lower sprocket keyed to the end of the main key, but when
        you cut the snout ring off you moved the new sprocket location
        so far back it won't engage any more.  A general machine shop
        can do this, but it's liable to be expensive.  It is,
        however, a relatively common operation for electric motor
        repair shops and some machinery places that supply keyed
        shafting.  Prices will run from $15 to $50 for the keyway.
        A simple half-round key is fine.

        Now you're back home, you need to fire up the Dremel tool
        or equivalent, gird your loins, hoist your petard, and
        grind on your pretty new journals.  You'll notice the oil
        holes, which were approximately centered before, are now
        shifted toward the sides of the journals.  That's because
        when you reduced the OD, the point where the drillings
        intersected the new, smaller OD is shifted.  As I
        mentioned earlier, there are at least two drilling patterns
        used on the Clevelands.  Hopefully you didn't get the one
        that shifts the oil holes a lot.  If you did, it's not a
        cause for shrieking and hair-pulling, but the engine will
        likely use a little more oil (due to more going past the
        sides and onto the cylinder walls) and have less oil pressure.

        To fix this you need to "hook" the oil holes.  That is,
        you're going to cut some lead-in slots into the crank to
        pick up oil from the groove in the upper main bearing and
        channel it off to the side where the hole in the crank is.
        Yes, this reduces the cross-sectional area of the crank a
        bit.  Yes, it technically reduces the strength.  The
        benefits outweigh the disadvantages; the cross sectional
        area is pretty far down on the list of potential weak
        spots, you'll be happy to know.  VW began doing it on
        all their motors in the early '70s; GM does it on quite
        a few fours and V6s, and the Chevrolet Power Guide from
        GM recommends doing it to all their motors except the
        big blocks.  The sizes of the lead-in grooves vary from
        1/8" deep x 1/4" wide x 5/8" long to 3/16" x 3/16" to
        1-1/2" long.  

        First you'll need to know *where* to grind the lead-in
        grooves.  Turn your engine block bottom-up, install the
        upper bearing shells, and drop the crank in.  I bet you're
        surprised most of the journals aren't even approximately
        centered over the bearings.  Looking at the block with
        the snout on your left, turning the crank in the direction
        of rotation (from the left, clockwise, or with the top
        moving toward you), look at each oil hole as it passes
        by the edge of the bearing.  Mark the crank with a grease
        pencil or felt tip on the side of the oil hole closer to
        you - remember, you are scooping the oil out of the bearing.
        There is one hole on each end main, the rest have two.

        Put the crank on your work surface, turn it to where the
        snout is on your left and the flywheel end on your right,
        prop it with something so it can't roll, and carefully
        grind a lead-in groove on for each oil hole on the #2, 3,
        and 4 mains.  Make it about 3/8" to 1/2" long, then hook
        it to the side at about a 45 degree angle to meet with
        the hole.  Use a grinding stone, not a cutter.  The cast
        iron is *very* hard and will dull even the carbide cutters
        quickly.  Now use a small stone and radius the lead-in hole
        where it meets the drilling; you want a nice smooth curve
        for the oil to follow.  Do not do the #1 and #5 journals
        (front and rear) yet!  If you do them it can cause problems
        with the balancing process.  You'll do them after balancing,
        before having the crank polished.

        Now turn the crank around where the snout is on the right.
        Grind a small (1/8 deep x 3/16 wide x 1/4" or 3/8" long is
        plenty) trailing groove on each rod throw *if* the oil holes
        are close - say, less than 1/8" - to the cheek side of the
        journal.  Angle the groove over toward the center of each
        rod's part of the journal, use about a 30 degree angle.
        You only have to do the ones which are close to the sides;
        the others will be just fine, though you might want to do
        them all just for symmetry.  Using a fine stone and low
        speed, break the edges of all the oil holes, main and rod.
        This means "remove the sharp edges", don't go nuts.  A 1/64"
        radius is plenty, and less is OK.

        The absolute last step is to polish the crank.  Arrange to
        take the crank as it comes off the grinder; after you're
        done with everything else, take it back to the shop and
        have them polish it when you're ready to do the final
        assembly.

        As you can see there's a considerable amount of work in
        cutting down a Cleveland crank to fit in the little Windsor.
        The other options are forged aftermarket cranks, at $900 to
        $1600, early '98 prices, or the Scat casting, which still
        seems to be in the $600 range, assuming you can actually
        find one.  I expect prices to drop; their 383 Chevy stroker
        crank can be purchased for under $200 if you shop hard.


(B) Rods:
        Now that the crank is mostly finished, measure (or have the
        shop measure) the width of the rod journals.  They will
        probably be a bit wider than stock due to the extensive
        grinding.  No problem - the rods are plenty wide and will
        need to be narrowed.  We'll take this as an opportunity to
        adjust the rod side clearance.

        The rod side clearance - the gap between the rods and the
        sides of the crank - is the end of the oil path.  If the
        clearance is too wide the cylinders will be flooded with
        oil and cause smoking and high oil consumption, and oil
        pressure at idle will be low.  Most racing shops now use
        narrower-than-stock side clearances for oil control.  You
        can't do anything about the side clearance in a stock motor,
        but we can in this one.  A narrow clearance will work fine
        for us too.  You want .008-.012 if you can get it.

        Take the width of each journal - they may not all be the
        same - and for each figure up the rod size.  Divide the
        journal width by two, then take .005 from each rod.  That's
        the rod width, for a nominal .010 side clearance.

        Narrowing the rods can be done on a milling machine, with
        some types of block surfacers, a Blanchard grinder, or other
        machine.  There's no real way to do it without big
        equipment.  Shop around; charges can vary quite a bit from
        shop to shop.  Some machines will leave a fairly rough
        finish.  It won't hurt anything, but you can touch it up
        cosmetically with a belt sander.  A belt sander will also
        let you take off a thousandth here or there to adjust the
        width.  I usually cut the rods with almost zero clearance
        and adjust the width with the sander for each rod pair.
        The sander removes metal slowly; it's not hard to keep the
        rod square to it.  If you're not careful you can sand the
        rod crooked, so you need a dial caliper or micrometer to
        keep track of things if you do this part yourself.

        When narrowing, metal needs to come off both sides of the
        rod to keep the bolt centered.  Some processes will also
        remove metal from the pin end.  That won't hurt a thing.

        Mark each rod of the pair with the number of the cylinder
        it goes to.  A number punch will work, or one of the metal
        scribes used for marking items in case of theft.  Mark
        the side opposite the oil squirt hole - the squirt holes
        point to the cam, the opposite side faces the pan rail.

        Now the pin end needs to be opened up from .912 Ford size
        to .927 Chevy size.  Actually, .925" if you'll be using
        a press fit.  You *can* use a floating pin, but you must
        use a bushing.  Steel-on-steel works for racing motors that
        don't last long, but you don't want that on a street or
        long track motor.  Eagle makes a very thin bushing that
        can be used.  The hole has to be honed oversize, the bushing
        installed, narrowed if needed, and honed again to the proper
        size.  Floating pins make assembly easy, but pressed pins
        are slightly stronger and a lot cheaper.  The machine shop
        will do all this on the rod machine.

        The next op is to resize the big end, which could have
        warped when you narrowed the rods.  Also, most stock big
        ends are neither round nor particularly accurately sized.
        Ask your machinist to size the big ends to the *small* end
        of the acceptable range; the bearings are held in by 'crush',
        the bearing OD being larger than the rod ID.  The tangs
        are just for locating the bearings during assembly!  To
        resize the big end the rod bolts must be removed to face
        off some metal from the bottom of the shank; now is the time
        to put in new rod bolts if you want.  In many cases new
        bolts aren't really needed, but you don't know if these have
        been stretched by some gorilla with a breaker bar, and you
        are wrapping a sizeable chunk of money in the project.  $50
        or so for a new set of bolts buys some peace of mind.

(C) Block:
        Have the shop check the main bearing alignment and deck
        flatness before they bore the block.  If either needs to
        be corrected, it might cost more than finding another block!

        The block will likely have to be bored, though it's not too
        unusual to run across a late 5.0 that mikes out okay.  Pistons
        are available in .020, .030, .040. and .060 sizes.  There
        is no .050; nobody knows why.  .020 is odd and hard to find.
        You'll likely want to stack with .030 or .040.  You're
        stroking the engine half an inch; I recommend going with the
        smallest overbore required to clean the cylinders up.  The
        longer stroke and shorter rods will increase the side loads
        on the cylinders, so I prefer to keep as much metal in there
        as possible.  After boring the block will have to be honed.
        Some shops use torque plates.  The small Ford isn't plagued
        by the bore distortion problems of, say, the small Chevy, so
        it's not really necessary to use torque plates.


(D) Trial Fit:
        Drop the bearings and crank in back into the block.  Take one
        of your resized rods, insert the bearings, and attach a piston
        with a temporary wristpin like the one you used for your
        clearance tool, or if you went for floating pins, just install
        the pin that came with the piston.  You don't need rings.  Now
        *carefully* turn the crank and watch as the rod bolts touch
        the bottom of the cylinder.  You'll have to grind the bottom
        of the cylinder for clearance.  You could mark the spot with
        a felt tip, but I prefer white model car paint and a small
        brush.  You want about .060" clearance left, right, and up
        around the bolt.  The zip tie will work again.  Now turn
        it the other way and mark the other side.  Some bores will
        take more clearance than others, a few might require some
        attention to the oil pump boss or pan rail.  That's because
        hardly any two blocks are alike.

        Remove the crank and bearings.  Use the Dremel or other
        grinder, or even a large round or half-round file, and remove
        the metal you marked.  Don't get too wild.  Now clean all
        the shavings out - compressed air (an air tank will work) or
        the water hose and a brush will do.  Now put it all back
        together again and make sure the zip tie will pass the closest
        point in each place.  If not, do it all again.

        If you happen to have a spare oil pump, distributor drive
        rod, and distributor around, now is a good time to make
        sure the clearancing you did on the front counterweight was
        sufficient.  If you plan on using one of the oversize drive
        rods, this is not an optional step.  Use a feeler guage or
        piece of cardboard; you need at least .020" clearance to
        the crank.


(E) Rod Bearings:
        The connecting rod bearings will now probably be too wide.
        They might not; they're narrower than the stock rods, and
        if the crank shop used a wide wheel to cut the rod throws,
        the bearings might fit unmodified.  We'll assume they need
        to be narrowed.

        The traditional method of narrowing the bearings is to make
        a mandrel or spud that holds a pair of bearings clamped over
        it with a radiator hose clamp, put the spud in a lathe, and
        face off however much of the bearing you don't want.  By
        the way, the amount you need take off will probably be
        different on each side; Ford doesn't center the bearings
        exactly in the middle of the rods.  Don't ask me, it's not
        my fault.

        Now, assuming you're tool-deficient and have no lathe, mill,
        or other equipment, you might find a general machine shop
        that will do it, or a high school hobby shop, etc.  Failing
        that, you can do it yourself with a Dremel and a sanding
        block if you're careful.  Either way, the bearings need to be
        .020 to .030 narrower than the rods, with no sharp edges on
        the outer shells or load-bearing areas.  Sometimes the tang
        locations vary in the rods; make sure the bearings fit *all*
        the rods acceptably.  You want all the bearings to be the
        same.  It simplifies balancing, and it will simplify things
        if you ever have to rebuild the motor.


(F) Balancing:
        Take your narrowed rod bearings, the pistons, the rings, the
        completely machined rods, the finished crank, and the harmonic
        balancer and flywheel or flexplate with you to the balance
        shop.  All the engines of this type I've dealt with have been
        balanced to 50 oz "5.0" bobweight instead of the earlier 28 oz
        "302" bobweight.  It will usually take one or two slugs of
        heavy metal in the front counterweight to achieve balance.
        If you didn't lighten the rod throws you'll probably need some
        in the rear counterweight.  Most shops charge "per slug" of
        heavy metal (a tungsten alloy) over and above the standard
        balance price.  So you're looking at $100-$250 for balance,
        plus $50-$75 per slug.

        It *is* possible to balance to 28 oz, but it will take more
        heavy metal.  I don't know how much more.


(G) Post-Ops:
        When you get the stuff back from the balance shop you'll need
        to cut the other lead-in grooves for the #1 and #5 mains (if
        needed) and have the crankshaft journals polished.

 You're ready to begin assembly now.  No, detailed as this is, it's
*not* a complete step-by-step.  This just covers the stroker-specific
aspects.  If you're an experienced engine geek you probably skipped over
half the stuff above anyway; if not, pick up a copy of "How To Rebuild
Your Small Block Ford".

 Good luck!


---Finale:

 No doubt you're surprised at the amount of work that goes into one of
these.  If you start looking around at kits you will find some shops
aren't quite up-front about total costs.  Obviously, most of them don't
include the block, which needs to be modified.  Less obviously, some of
them aren't balanced.  A stroker *must* be balanced or it will blur
your eyeballs before it starts chucking bits out the oil pan.  You
probably noticed the largest amount of time and money went into the
crankshaft.  It will pay to shop around.  If you don't have a local
shop that is willing to do the work you'll have to look at mail order.
Most mail order places only want to do 3.4" stroke 347 cranks due to
the labor cost, but if you can bargain them into doing everything
*except* clearancing the counterweights you might come out ahead.
Finally, the price of forged cranks seems to be dropping slightly,
and Scat may yet drop the price of its custom casting.


----------------------------------------------------------------------
              How To Build A 347 To 355 Inch Stroker 302

                       version 1.03, 09/02/1998

         Copyright 1998, Dave Williams.  All rights reserved.
        May not be reproduced without permission of the author.

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