79 350 misfire question

I have a 79 chevy big ten with the 350 of course and it ran good only mis fired with the quadrajet when i really romped on it so I awitched to a edlebrock 600cfm carb and with the stock intake had to say bye bye to the egr and plugged all the old vac lines and when she first starts up backfires on the driver side and when i give it gas it will back fire i suspect timing is the issue but can it also be a lean backfire how can i test this? and i also switched to tubular headers and its open for now till i can figure out this issue it also dies when I put it under load ex put it in gear any help would be hugely appreciated

I have a 79 chevy big ten with the 350 of course and it ran good only mis fired with the quadrajet when i really romped on it so I awitched to a edlebrock 600cfm carb and with the stock intake had to say bye bye to the egr and plugged all the old vac lines and when she first starts up backfires on the driver side and when i give it gas it will back fire i suspect timing is the issue but can it also be a lean backfire how can i test this? and i also switched to tubular headers and its open for now till i can figure out this issue it also dies when I put it under load ex put it in gear any help would be hugely appreciated

Double check firing order and dist. for shaft wear and advance operation also cap and rotor for problems like cracks and moisture.

thanks for the info il check this weekend i will report what I found

Hmm, Mopar Man, try this Max Wedge on for size.

If I read your post right, the back-fire got worse with the carb change?? With the Q-Jet it could have been the secondary air valve adjusted too loose.

Did you install the EDL on the Q-Jet manifold? If so did you install the correct adapter for this conversion?

sorry guys for the late reply work get home work on the truck some more I put a performer series 600cfm carb on with the adapter plate for it from edelbrock and a egr delete plate and i chaned the cap and rotor which it was somewhat due for checked my wires one had a little bit more resestiance than I liked so I changed them all out now it runs well it only back fires when I hit the gas and let it idle down but it aint through the carb now and it wont idle I have to keep my foot on it just a bit to keep her running

Sounds like a vacuum leak or lean /misadjusted carb.

sorry for the late reply work has me running like crazy and I found the leak it was the egr valve and they are about 80 bucks so is it a smart choice to just block it off with a plate or would it be smarter to just bite the bullet?

sorry for the late reply work has me running like crazy and I found the leak it was the egr valve and they are about 80 bucks so is it a smart choice to just block it off with a plate or would it be smarter to just bite the bullet?

If you want good gas mileage and engine to run good for a long time replace it.
On price sounds little high.
Shop around.