carb sizing - The 1947 - Present Chevrolet & GMC Truck Message Board Network

KyFarm · 12-18-2019, 01:21 PM

I am about to pull the plug on a Chevy HT383.

Some literature from Chevy says to go with 770 cfm carb
Other lit from Chevy say to go with 670cfm

Called Holley and they said Chevy always oversizes their recommendations for crate motors and they don't know why.

Holley ran math and said a 570 is what is perfect for the HT383.

Any thoughts on what size to go with?

Motor will never see the top of the rpm band, 69 K10, just want to drive it around the country roads around my farm.

12-18-2019, 01:21 PM	#1
KyFarm Registered User Join Date: Sep 2009 Location: Taylorsville, KY Posts: 261	carb sizing I am about to pull the plug on a Chevy HT383. Some literature from Chevy says to go with 770 cfm carb Other lit from Chevy say to go with 670cfm Called Holley and they said Chevy always oversizes their recommendations for crate motors and they don't know why. Holley ran math and said a 570 is what is perfect for the HT383. Any thoughts on what size to go with? Motor will never see the top of the rpm band, 69 K10, just want to drive it around the country roads around my farm. __________________ KyFarm's Build/Need help thread 1969 K-10, Short Step, (383HT/4L70E soon)-NP205



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