68 charger

hi
new here need some help. machine shop said it is 433 383 block .040 flat tops 440 crank . 906 heads. don't know cam size. has dual quad intake carter 390cfm carbs. 727 2000rpm stall. can't get to run right stumbles like turn off then go's. backfires if timing is under 45 btdc. tried single 4bl intake still same problem. up metering rods got better power but still stumbles.
appreciate any ideas thanks

PK1

1. Who put dizzy in? Was it indexed correctly?
2. Back fires thru the intake or out the pipe?
3. Does it idle and what is your vacuum at idle? Whats the needle doing?

68 charger

thanks for help. I put distributor in it's stock. had Mallory dual point ran worse. backfires in intake. exhaust was popping be for upping metering rods. idles ok at 800rpms at 550 really lopes. don't have vacuum gauge. checked for vacuum leaks don't see any. sorry for not having all info.

Archer

68 -

Kinda sounds like you've got a couple of plug wires crossed.

Archer

68 charger

just checked wires look ok 18436572