This is topic experienced engine builders advice needed! in forum Tech Talk at Northern California Ford Owners  .


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Posted by mrsmcizzle (Member # 9643) on :
 
Can gt40 heads be put on an '86 roller motor (stock) Without any issues? All advice is helpful. Thanx in advance
 
Posted by OneFastHatch. (Member # 9537) on :
 
Yes
 
Posted by triple b (Member # 8763) on :
 
check piston to valve clearance. I believe those are dished pistons but there is a ridge on the outer edge of the piston that may hit with bigger valves
 
Posted by LXjames (Member # 10791) on :
 
85 motors have notched pistons but sit higher
86 is flat no notch but sit lower
87+ had notched pistons not sure on depth but check what cam you can use and then make sure you do your own measuring
 
Posted by mrsmcizzle (Member # 9643) on :
 
Im just running the stock cam im.not doin anything special to this motor. Im.just tryin to put it together without any problems. Are all the harmonic balancers interchangeable 79-86? Or bcuz the earlier 302s arent rollers the 79 balancer wont work for a 86?
 
Posted by mechanicalsnake (Member # 11845) on :
 
Stock gt40 heads would install with no issues! Factory pedestal mounted rr would be suggested since not major build. If stud mounted, measure pushrods and replace if needed! Factory style has broader surface and will not damage guides if a little off!
 
Posted by turbo50 (Member # 6700) on :
 
Hang on.

If you run factory roller rockers, pedestal mount, they will be 1.7 ratio. They never put 1.6s on anything from the ford factory with pedestal mount and roller body.

With the larger valves of GT40 style heads and the added lift from the 1.7s and the unique compression height and surface of the 86 style pistons, please check piston to valve clearance as you are even more limited using your 86 piston.

Also, the size of the rocker tip can not make up for incorrect push rod length and in theory a larger surface area contacting the valve stem tip may look good but in reality, it will provide even more side loading if you have improper valve train geometry because you now have more leverage and a larger contact area.
 
Posted by CoyoteCoupe (Member # 9621) on :
 
Turbo50 is the man!!
 
Posted by mrsmcizzle (Member # 9643) on :
 
Jesus... smh so after i check the piston to valve clearance what do i do next? Should i use thicker gaskets? Are all of the 302 harmonic balancers the same? Can i use a balancer off of a 79 flat tappet 302?
 
Posted by LXjames (Member # 10791) on :
 
If you have an 86 block you need a 50z balance dampener the one from a 79 is a 28z balance so it won't work
 




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