Ok, i have converted my 305 from TBI to carb along with ported 081 heads, bigger cam and edelbrock intake. At first i set the timing at 0 degrees and everytime i would hit the gas it would backfire and shoot a flame out the carb, then i advanced it and little at a time it got better to where i finally ended up at about 12 degrees. Well i was running it again today and i shot a flame out again, but only once under heavy load so i advanced it some more to maybe 14 degrees. IS it dangerous to the engine to advance the timing too much? hopefully it wont do it any more but i dont want to advance it to much to where it will harm something

 

yes, advancing it to far can cause damage, a bit won't hurt alot can

 

Ok well how much is too much? Is it ok to run 14-18 advanced? When i use the timing light, the mark is all the way to the end of the timing tab on the left

 

???

 

you got rid of the computer type distributor and got one with vacuum advance right? if not then thats your issue

 

Yes i have HEI vacuum advanced distributor

 

When it starts knocking, you've advanced it too far.

 

well i advanced it to about 14 and just now it blew another big flame, so now what?

 

How sure are you that the plug wire routing and timing marks are correct?

 

100 percent positive, i have re checked it 50 times. If the fuel pressure is too high will it cause this? Its like i have to try to get it to do it, if i rev it up pretty high then let the RPM's drop and stomp the crap out of it again, it shoots flames

 

What about the timing marks? Did you use a piston stop?

 

Timing marks? YOu talking about on the timing cover? ( Edited my previous post)

 

If the fuel pressure is too high the float bowls will overflow and it will flood or the engine will load up and run rich.

 

SO then could this be my problem? Im was running about 6 PSI

 

6 psi is fine.

 

Darn. well what next? Should i advance the timing some more?

 

So when the revs are up while you're at WOT, and then if you let off the throttle and slam it back down again it backfires through the intake?

 

Yes only its when i let run back down to almost an idle, but i really have to slam the pedal. Im afraid thought that when i drive it and put it under load it will be a little worse. Think maybe it could have something to do with the secondaries or the choke? Also i havent got the carb completely tuned yet with the Idle Mixture screws

 

Tune the carb.

 

or just put in a higher octane

adjust your idle

 

So this could be causing it? Is a tach and dwell meter good to use?

 

A tach is useful, a dwell meter isn't. What kind of carb did you use?

 

im using edelbrock 1406

 

Well, i got her tuned with a vacuum gauge. I got it to its peak vacuum at about 11. Then i took her down the road and now it is really starting to unleash its potential. Only thing i noticed is that its still has a little bit of hesitation in it and i noticed a little bit of racket that sounded like valve train, or spark knock. i think i will try to go back to about 12 degrees on the timing

 

Have you recurved the distributor yet?

 

What does that mean?

 

https://www.thirdgen.org/newdesign/tech/hei.shtml

 

i set my timing by using the total timing, what that means is i dial in 36 degrees advance on my timing light and run the rpms up over 300rpm (your mechanical advance should be fully advanced by that rpm) and i line up the timing mark on the balancer with zero on the tab. i also do not run a vacuum advance as it does nothing for performance, it is only to help fuel economy at cruise.

 

Well i am not using an advance light, just a regular style. The mark on the balancer is all the way to the left end of the timing tab. But im almost certain that it is spark knock, i unhooked the advance on the distributor and it still did it. Also i noticed that i could hear it right when i start the engine then went away.

 

You don't need a dial-back light, just make a new mark on your balancer 36 degrees from the TDC mark.

 

So i need to set my base timing at 36 degrees? Its knocking now, wouldnt that make it worse

 

del: what is the octane you are running? try running 93, it should stop the knock. I have mine set @ 45 with the computer and i run 93 and i am fine.

 

no base timing would be around 10 or so depending on the amount of advance you have in the mechanical advance of the distributer.

 

Im not sure but i dont think its 93.
I set the timing back to about 12 advanced, i fould out that i had it to about 16