Carb choice for 350 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*Billla* · 10-08-2007, 09:13 AM

Been posted a million times, but:

CFM = ((CI x RPM)/3456) x VE; VE for a stock engine is around 75% (optimistic).

This means for a square bore you don't need the secondaries until 4000 RPM, and you'd have to turn 8K to need more than 600 CFM

Another vote for a good overhaul on your existing Q-Jet. They're great carbs and typically just need a little TLC. The only problem is tuneability - there just isn't great availability on jets and rods any more

After the Q-Jet, any good vacuum secondary carb of 600-650 CFM is a good choice.

10-08-2007, 09:13 AM	#25
Billla Account Suspended Join Date: Sep 2005 Location: Monroe, WA Posts: 3,815	Re: Carb choice for 350 Been posted a million times, but: CFM = ((CI x RPM)/3456) x VE; VE for a stock engine is around 75% (optimistic). This means for a square bore you don't need the secondaries until 4000 RPM, and you'd have to turn 8K to need more than 600 CFM Another vote for a good overhaul on your existing Q-Jet. They're great carbs and typically just need a little TLC. The only problem is tuneability - there just isn't great availability on jets and rods any more After the Q-Jet, any good vacuum secondary carb of 600-650 CFM is a good choice. Last edited by Billla; 10-08-2007 at 09:13 AM.



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