Got a Rochester 4 brl 400 68.
Had my carb rebuilt last year but just now got around to putting it on, don't have a Chiltons handy and was wondering if theres a ballpark procedure for adjusting the mix screws on the card.

Bird fired right up, but is running chuggy for now, as expected.
Hasn't been run in over a year, so I got some tinkering to do before she is road worthy.
Is also backfiring a bit, one loud one out the tailpipe just as I was bending down right by it, to open up the garage door before I turned purple.
Didn't have the door open cause I didn't expect it to fire up so soon like that, was a pleasant surprise.

Am open to suggestions also why my sig pic ain't showing up.

Turn both idle mixture screws all the way closed. Turn them both out 1 1/2 turns. Hook up a vaccum gauge to the intake manifold and start the car. Adjust both screws out about 1/16 turn at a time until you maximize intake manifold vaccum at idle.

Thanks I'll give that a shot