samsonhusky

My car will backfire through the carb but not all the time. If I'm cruising at a certain rpm then hit it, it will backfire, but if i"m accelerating at all fast are slow and hit it, it does good no backfiring. And for as just driving around it does fine. Any ideas on what I need to check for. This is on a 85 with stealth intake and new holley 600.

projectresto83

Check your timing, it is off slightly.

samsonhusky

Timing sounds easy enough I set it when I first put the motor in and haven't touched it since. I have it set on 14 deg think i need to go up are down with it. And maybe 1 deg either way. I have gt-40p heads e303 cam stealth intake and holley 600

Gary H

Sounds like it's going lean. Might need to change the Acc pump cam.

projectresto83

You are still running the vac advance dizzy correct? Run it without the vac supply to the dizzy. I had a similar problem with my 83.

1988TTOP

y would u not run the vac line to the dissy ????

mjr46

some set ups were liberal with the advance, I've seen some stock dizzy's even my own one reach a total advance of 45-50, and the ideal norm is all burning should take place before 36 -38 max, anything after that is just wasting fuel

1988TTOP

ok cool thanks

projectresto83

I ran mine without the vac advance for awhile and then for some odd reason when I accidentally ripped apart my dizzy wires the timing was off again so I reset it and then the vac advance worked perfectly fine. I don't know what happened but it fixed it. It may hamper your performance slightly but thats about it. I didn't notice any fuel milage difference.

samsonhusky

Thanks for the help it was the timing I didn't have the vacuum line off of the dizzy when I set the timing the first time it was way off. No more backfiring and that thing will fly.