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If your car pops or backfires when you whack the throttle the problem could be the accelerator pump. Make sure the accelerator pump is flowing fuel through the whole throttle stroke. A bad accelerator pump will cause a temporary lean condition which will cause the engine to pop.
Also, try your timing a little higher. I would start at 12 to 15 degrees and see if you get any pinging. Retarded timing can also cause a backfire.
I run my 454 at a total of 40 degrees timing. Mine is actually set at 20 degrees initial with the mechanical advance putting in another 20 degrees by 4000 RPM but I don’t run a vacuum advance on mine.
Bill Vander Werf
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I am doing the same thing with my BB. I just installed a new hyd Comp Cams roller and am using a mechanical advance Mallory Unilite. Comp Cams help line said that 36 -38 deg total was recommended w/ 8 -10 initial for my cam. The cam # is CB 290-R10. The Mallory is set at 25 deg total advance, and is at 9 deg initial now. I have ordered a Mallory kit to change the total setting. I do not plan to change the springs. I rebuilt the 750 Edelbrock AFB. The valves are zero plus 1/2 turn down. My problem is that it back fires occasionally. Could it be a vacuum leak. The cam was installed at zero. Have new Taylor Wires to install today. New carb? I'm at a loss. Any suggestions? |
