Engine 1966 backfire through carburetor

[Malibujoel]

I just completely rebuilt my 289 with a high lift cam and roller rockers. Double springs on valves and heads were rebuilt. Bored .40 over. Replace carb with new Edelbrock AVS 2. New fuel tank. New HEI distributor. New 2500 stall converter. C4 trans. Car idles good and revs nice. When I put it in gear it falls on its face and backfires through carb under excelleration. I tried power braking in gear and tried reving motor and it Boggs and backfires through carb and motor will die unless I put it back in park. Any suggestions would be greatly appreciated!

 

[WORTH]

valves out of adjustment, or timing is off. Who rebuilt the engine, is the cam timing correct?

 

[Malibujoel]

valves out of adjustment, or timing is off. Who rebuilt the engine, is the cam timing correct?

Good morning Worth.
I accidentally installed spark plug wires firing order for a newer 5.0 and was totally off as it causes only half the motor to fire on time. I rerouted all wires and she runs like a champ. Thank you for your feedback. Always appreciated!
HAPPY NEW YEAR!

 

[WORTH]

Don't ya hate it when they take a perfectly good firing order and change it???

 

[DBegley]

And that is why my Dad told me many times to change ONE plug wire at a time.