Need help, intake backfire

blackstangt

Member
May 31, 2004
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ny
just about everything in the engine compartment is brand new, but all old stuff worked right and i bought a 340 hp gt-40 crate motor from ford. i think it may be defective(cam/valve timing) from ford, any ideas? does the egr need to have vac directly form the intake?
 
When you installed your distributor, was the #1 piston on top dead center of the compression stroke? It is easy to accidentally install the dist 180 deg off, and this could cause a backfire through the manifold (intake valve begins to open before TDC of exhaust stoke.)
 
I may have gotten ahead of myself. First make sure the plug wires are going to the correct cylinders. The firing order is 1,3,7,2,6,5,4,8 moving counterclockwise. To check base timing, rotate the engine to the 10deg before top dead center mark on the balancer, and pop the distributor cap. The arm should line up with either the #1 or #6 cylinder position on the cap.

If that checks out fine, you may be 180 deg off.

Check out this link:
http://forums.stangnet.com/showthread.php?t=485462