The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - What kind of gas mileage do you get with your 67-72?

i82much · 02-08-2021, 11:38 AM

if you have a holley, i understand reducing the main jet size and increasing the PVCR to compensate can really lean out high speed cruise AFR. Lower speed cruise is tougher because you have more idle circuit in play and there is a lot going on between the ifrs and iabs. But i bet most guys with a holley could pick up a mpg or 2 just by playing with the pvcrs and main jets.

02-08-2021, 11:38 AM	#110
i82much Registered User Join Date: Jul 2008 Location: Bowie, MD Posts: 313	Re: What kind of gas mileage do you get with your 67-72? if you have a holley, i understand reducing the main jet size and increasing the PVCR to compensate can really lean out high speed cruise AFR. Lower speed cruise is tougher because you have more idle circuit in play and there is a lot going on between the ifrs and iabs. But i bet most guys with a holley could pick up a mpg or 2 just by playing with the pvcrs and main jets.