ok first off my car went through 5 gallons of gas in less than 2 hours of idling and driving in my small neighborhood. i have an edelbrock carb 600 cfm weiand high rise intake and comp cam. my timing is off because i dont have a timing light but im playing the guessing game to where it runs right but im getting a light tomorrow. it backfires when i goto put it in D or R but if i goto put it in N and P it doesnt backfire could the timing be the only thing doing this.

 

It could be, but you won't know for sure until you put the light on it. Always fix the known issues first.

 

I'd invest in a timing light. At least then you'll know where it's at and where it needs to be.

 

What motor was this? Replaced the distributor with a vac advance model?

 

it was a 305 tbi i swapped to a 350 carb'd. i put a light on it and i moved the spot on the balancer to where the tab is and its still backfiring idk what to do and i put 3 gal of gas in it and it was gone with in 30-45 minutes just idling.

 

and yes it is a vac advanced dizzy now