Backfiring out carb and wont run right

Ok, now for the "come clean"...


I agree with Del, to do a compression check next. Make sure that you have good compression and that the cylinders are close in compression.

This neighbor who is a "mechanic on and off"...

Not knocking the guy, but the distributor drive gear can be a little tricky for new "mopar" builders. If he is not familiar with SB mopars, the distributor drive gear slot may not point to #1 cylinder when it is at TDC. This is very easy to fix.

1. Make sure that you know where your TDC is. A dead stop tool is the best way to find it.

2. Once you know for sure where TDC is, then put the engine at TDC and remove the distributor cap. Where is the rotor pointing? Make this the #1 spark plug wire location for the distributor cap. Then follow the firing order around the distributor cap in the direction that the rotor spins 1-8-4-3-6-5-7-2.

3. Then manually put the engine at 10° BTDC with the marks on the damper and turn the distributor so that the rotor points at/has contact with the #1 wire position on the distributor cap.

4. Try to start it and adjust the timing from there. You should go for 34° - 36° total advance at 2000 - 2500 RPM.

Positioning the distributor gear is difficult for some beginners to the SB Mopar.

And yes, make sure that you are on the compression stroke when the distributor is at #1, or you may be 180° off as stated above. That is easy to fix by just loosening the distributor and spinning the rotor 180°.



Also a key rule:

If it backfires through the exhaust, you may be too far advanced on your timing.

If it backfires through the carb, then you may be too far retarded on your timing.