holley 4160 carb jetting

[special70gmc]

i know this should be in drivetrain but it will bes seen more here, anyway i have a holley 4160 the # is 80508 and mortec says its jetts are (F)72 (R)plate 134-21 6.5 the problem is my moter is running really rich. i havent actually driven it yet but it smokes black and loads up at idle, i like to lean it out some what should i do or i should say what jetts should i purchase? the engine specs are

355cid LT-1
10.3-1 compression
total seal rings
comp xe274-h cam w/comp roller rockers
vette ''492'' castings w/bowl port
2.08/160 manly ss valves
forged + balenced rotating assembly
1 5/8 headers 2 1/2 exaust w/flows +h-pipe
rpm airgap intake
holley 750 dp
msd distributer + 6al box
tci street fighter trans w/2400stall
4:10 posi rear
actually alot of people say w/this motor it shouldnt need to be leand out but obously it does thanks alot - kyle