Author
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Topic: experienced engine builders advice needed!
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mrsmcizzle
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Member # 9643
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posted
Can gt40 heads be put on an '86 roller motor (stock) Without any issues? All advice is helpful. Thanx in advance
Posts: 166 | From: oakland, ca | Registered: Dec 2009
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OneFastHatch.
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Member # 9537
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posted
Yes
-------------------- 1991 fobra (slow)
Posts: 2139 | From: bay area | Registered: Oct 2009
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triple b
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Member # 8763
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posted
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
Posts: 1730 | From: sacramento ca | Registered: Nov 2008
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LXjames
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Member # 10791
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posted
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
-------------------- On Point Motorsport prez. King Lx
Posts: 4761 | From: Pittsburg CA | Registered: Mar 2011
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mrsmcizzle
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Member # 9643
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posted
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?
Posts: 166 | From: oakland, ca | Registered: Dec 2009
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mechanicalsnake
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Member # 11845
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posted
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!
Posts: 42 | From: San Jose | Registered: Mar 2012
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turbo50
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Member # 6700
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posted
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.
-------------------- .........when was the last time YOU built something with YOUR own hands?
I offer quality sidework at reasonable prices. PM ME
Posts: 7606 | From: Discovery Bay, California | Registered: Apr 2006
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JON_SVT
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Member # 9621
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posted
Turbo50 is the man!!
Posts: 2608 | Registered: Nov 2009
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mrsmcizzle
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Member # 9643
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posted
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?
Posts: 166 | From: oakland, ca | Registered: Dec 2009
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LXjames
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Member # 10791
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posted
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
-------------------- On Point Motorsport prez. King Lx
Posts: 4761 | From: Pittsburg CA | Registered: Mar 2011
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