318 tuning question

[Jbland]

Ok so I have a 68 charger w a 318 bored over 30 with an edelbrock 4bl carb. I recently put new plugs and performance wires in it as well as a cap and rotor. Now before starting it back up I ran mixture screws on carb all the way in and then backed out a turn or so. Now the engine is backfiring thru exhaust at idle.already checked firing order and it's correct? Any suggestions as to whether this is mixture related or timing/ignition components?

 

[Dako]

Back firing at idle is most likely a couple swapped wires. Ask me how I know...as youngsters, I think we all have learned (the hard way...well, at least for me) that taking ALL the plug wires off at once, vice replacing one at a time is an invitation to mis-indexing the firing order. I once verified mine (twice!), then a buddy (Chevy buddy at that!...how embarassing, right?) found the two guilty strands.

Gotta ask...You are verifying by tracing from the distributor and not from each cylinder bank (head), correct? Tracing from the head(s) to the dist. makes it easier to miss the swapped wires.

 

[RustyRatRod]

Double check number 5 and 7. I been buildin and tunin on engines thirty plus years and I still swap them two sometimes. 1-8-4-3-6-5-7-2.

 

[70rr-brian]

Put the old cap and rotor back on and see if it clears up.