4 speed makes it easier to set up at idle. That isn't a DP carb... It's a vacuum secondary.
You have to get a timing light on it. Hillbilly timing tape the balancer if you need to.
If it cranks over easily now, turn the distributor a bit counter clockwise until it is hard to crank over. Then back it off some.
DO NOT drive it that way until you have a the timing sorted out. Only thing this does is give you an idea where the timing can go. Set the idle around 900 and try to get control of the idle mix screws. See if it cleans up.
I have a 292 cam in a 340 and it has 30+* of timing at idle, but is an auto car. I hate that engine... lol Didn't build it and no idea where the cam is installed, likely not where I would want it.