Carb help needed

[niles]

Justing getting it on the road. Carb very rich.
Have new 3110-4 750 cfm Holley, on cobra repli. 2200 lbs; 396 CI cleveland stroker eng; 4V heads @ 300 cfm. medium hot cam. Have O2 sensor installed so I can get A/F ratio directly. Float levels are good; float valves are sealing, when running electric fuel pump with sight screws out; fuel level remains right at bottom of opening.

Problem: out of box- very rich; idle screws will effect idle. idle - vaccum about 6 to 7 in hg. at 2000 rpms about 14 in. came with 6.5 pv and 72 jets. o2 reading of 850 to 950 mv. Plugs confirm rich - very black and starting to miss after about 60 miles.

changed jets to 70; same reading on O2 sensor. No better.
Thinking the PV was bouncing open at idle of low throttle; changed PV to a 4.0; Suprisingly went much richer; O2 is up to 1250 mv and fouls plugs in about 1 mi.

This has got me stumped; motor seems fine; no miss; scarey power at 5000 rpm; just very rich; about 7 MPG.

HELP

gn


HELP