[question on checking out some newly-aquired aftermarket small block Ford cylinder heads before installing]
Check the seal-to-retainer clearance. Ideally you want .060" clearance at full lift.
Pour gasoline or rubbing alcohol into the ports. There should be no more than a *very slight* seepage over a few minutes.
Eyeball the keepers and make sure all of them are sitting down in the retainers, and the retainers all look to be the same height in relation to the valve tips.
Figure out which spark plug you need *before* you put the heads on the motor.
Check to see if they're for 7/16 or 1/2" head bolts, and make sure you have the correct bolts, washers, or bushings if needed.
Check to see if the heads take different length bolts from your old ones! Some aftermarket heads require longer bolts since they're thicker at the bolt pads.
If you're running a non-adjustable valvetrain, disassemble and clean one intake and one exhaust lifter so the plunger can be depressed, and used those to make sure you're within the pushrod travel limits.
Check the rocker wipe pattern on the valve tips.
Make sure the water holes on the deck surface are all covered by your head gasket.
Make sure the intake and exhaust manifolds line up, with particular attention to the water passages on the intake surface.
If the exhaust ports are raised, check header fit before tightening the heads down. Checking plug-to-header fit is also a good idea; some older Darts had severe problems, worse than the GT40Ps.
For that matter, make sure the bolt pattern on the exhaust ports is the same as your headers; many aftermarket heads have relocated bolts for more tube clearance.
See if they have the proper bushings or blockoff plugs for the EGR crossover, if present.
If racing heads, verify any necessary accessory and sender holes are present.
It would be a good idea to clay a piston, shim the test lifters to full height, and check valve to piston clearance. Most aftermarket heads have larger or relocated valves and may require notched pistons with some cams.
"Checking is free, replacing broken parts costs money." > Return to Dave's home page