Engine: 250 inline, Thrifty cam(.512 lift, 212 duration, 110 LS), 1.84/1.6 valves, intake lumps, fresh rebuild, 15" vacuum at idle (not in gear)
Carb: 600 cfm 4 bbl Holley 0-80458SA, 62 primary main jets, 64 secondary jets, 7.5 Quick Fuel 4 opening PV, stiff black secondary spring
Car: 1964 Nova, TH350 trans with 2400 stall converter, 3.08 gears

Problem: When driving up a mild hill at 50-60 mph and 1/4-1/2 throttle opening the AFR goes down to 10.5-11:1. At WOT on the same hill the AFR is 12-12.5:1. Vacuum is below the 7.5 PV opening. RPM is about 2400-2500.


I'm thinking the PV is opening too soon and/or the secondaries are not opening enough. Are either of these worth trying or is there something else? Thanks

Adam