i have a fresh built 9.7 comp 340 stroker 418 cid,idle vacuum is 11",timing set at 35*,cam is a herbert solid roller .246/.253@.050 lift is .585in/.600ex,installed at 103.5 icl.carb is a rebuilt 750 db pumper 4779-2.has a 6.5 pv.,72 f/82r jets,im trying to clean up the idle some. i set the idle mixture screws with a vacuum gauge,they ended up roughly 3/4 turn open its a 4 corner idle.do i need to crack open the secondary plated some?or should i drill holes in the throttle plate?looking for some ideas?it runs real good above idle, just little rough idling is all,thanks mike

That might be the distributor. What do you have the lead timing at, and how much is the mechanical advance adding?

Holes will help a carb idle that has too much transfer slot open to idle better As you said you can crack the sec open too and possibly get away from the drill

timing is at 23 base, total is 35, the balancer is tough to read its a bhj billet that is real shiny,i put a black mark on it when i verified tdc, i might end up puttting timing tape on it or painting it to get rid of some of the glare.

Hey Mike, nice to hear you got your motor running. Any video yet? I use Don's from FBO method to set carbs, Idle and mixture adjustments. The motors I tune Idle great in park and in gear........Matt

thanks matt.no video yet i will have to figure that out next.

matt: mind shareing the method with other moparts members? dave

Is 23° the highest idle vacuum?

i did not try rotating the dist, to the highest vacuum reading, i was using the vacuum gauge to set the idle mixture screws.

Hello,

Get the timing figured out before you do any real tuning with the carb.

Damon

what should my base timing be set at ,distributor is older mp distributor ,msd6al box with blaster 2 coil.

Should initial be set for highest idle vacuum? Then adjust distributors mech advance to get the desired total timing?