[cuuntree_boy]

the carbeurator on my 1986 chevy 305 backfires through the carbeurator and wont start. i recently had to have a broken valve cover bolt fixed so i had to take the carbeurator off but it ran fine before i removed it. also it is timed correctly. any help here would be greatly appreciated

[DaSouthWon]

If you're sure that your timing is correct, and no adjustments were made to the carb while it was off look at your electric choke connections to make sure they are correct. Make sure it wasn't wired back in line with your coil or in some manner that would cause a sporadic spark. If it's a quadrajet check the filter where the fuel line goes into the carb. You may have jarred some funk loose and clogged the jets. Only other thing that comes to mind is a massive vacuum leak. Dunno, but double check your timing.

[327supreme]

dont know if this is your problem or not since it was running fine before but i had the same proble.i bought a fuel pressure regulator and set it at 4.5 lbs and mine straightened out

[kleen56]

I agree with dasouth, it sounds like a timing problem. It sounds like the timing is too far advance causing the valve timing etc to be off, thus the backfire. I'd also check to see if the timing chain is worn. It may have skipped a tooth which will really cause problems.