so i have a holley 80592s i put on my boats stock 5.7 vortec. trying to dial it in. i did run the power valve line to vacuum on the manifold. run the motor, sounded good, run it all weekend at the lake . it has a stumble at sec. so i did some research and want to know it this is true. if you dont run a pv in the sec. the vets should be +8 from the front. so i had 65s int the front and 69s in the back..i guess iam lucky i didnt melt it down..the plug look ok not to lean but could go a little richer..so em i on track here with dialing this thing in, or em i way off????????????btw iam using this carb cause it was brand new and free....the carb is a 80592s 4150 600cfm dp...any help would be great..
The number of size increase is determined by the size of the PV restricter. If the resricter is small, the difference in the jetting will be small. Most blower carbs have pretty small resrcters. The PV circuit is almost a waste on a blower deal. So the enriching from the PV is modest. Your stumble is most likely caused by the fact that the PV has a rating of about 4.5 in a blower carb and you should be up around 6.5. Your probably getting into the secondaies and still haven't opened the PV in the primary. And it just goes lean. Its just opening late, this is if the stumble comes from a slow acceleration up. If it happens on a sudden opening, the shooters may possibly be too big, and the pump itself too big. Those things have dual 50cc pumps. Thats a little more than a stock 5.7 cares to see. First change the PV to a 6.5.
so i got into the carb today and re jetted to 67 fronts and 77 backs, i called holley and they said if there is no pv in sec. you need to jett +8 higher in the rear. so i got the specs online and did just that. the pv is a 6.5 in the front. iam testing tomorrow and i will post.