GMC 305e Carburator Choice - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**DreamRyder1963** · 04-29-2014, 01:49 PM

My brother and I are starting to think about doing some slight performance mods to his truck. The truck is running perfectly now so this is just us brainstorming for the future. I have picked up a second intake for us to work on while he continues to drive the truck. According to 60-66 GMC Guy, a 500 cfm 2 barrel Holley is a nice choice for these engines. While we both like this idea, he is still in high school and getting ready for college so money is an issue. Would a 600 cfm Holley 4 barrel be to much for this engine? I tested the fit of a 2 to 4 barrel adapter this afternoon and it fits fine. I ask because I have a spare 4 barrel right now and this would save him a nice chuck of change.

**Bob B.** · 04-29-2014, 03:51 PM

The V-6's really run well with the Holley 500 c.f.m. 2 bbl.. I don't know of anyone who successfully got a 4 bbl. on a 305, but it has been done on the large 401's and 478's. I guess all you could do is try. You might end up spending more on gasoline over time then you would buying the 2 bbl. now. The guys on the 6066GMC page are very knowledgeable about these engines.

**DreamRyder1963** · 04-29-2014, 08:10 PM

I figured it was unlikely. The more I look at the intake runners the less I think it will work.

04-29-2014, 01:49 PM	#1
DreamRyder1963 Senior Member Join Date: Jul 2012 Location: Knoxville, TN Posts: 499	GMC 305e Carburator Choice My brother and I are starting to think about doing some slight performance mods to his truck. The truck is running perfectly now so this is just us brainstorming for the future. I have picked up a second intake for us to work on while he continues to drive the truck. According to 60-66 GMC Guy, a 500 cfm 2 barrel Holley is a nice choice for these engines. While we both like this idea, he is still in high school and getting ready for college so money is an issue. Would a 600 cfm Holley 4 barrel be to much for this engine? I tested the fit of a 2 to 4 barrel adapter this afternoon and it fits fine. I ask because I have a spare 4 barrel right now and this would save him a nice chuck of change. __________________ 1971 Chevy C10 Cheyenne (sold for Mazda) 1963 Chevy Corvair Pro-Touring Project 2012 Mazda 3 i Sport sedan http://www.dracoautodesigns.com/

04-29-2014, 03:51 PM	#2
Bob B. Senior Member Join Date: Aug 2005 Location: Los Angeles Posts: 1,321	Re: GMC 305e Carburator Choice The V-6's really run well with the Holley 500 c.f.m. 2 bbl.. I don't know of anyone who successfully got a 4 bbl. on a 305, but it has been done on the large 401's and 478's. I guess all you could do is try. You might end up spending more on gasoline over time then you would buying the 2 bbl. now. The guys on the 6066GMC page are very knowledgeable about these engines. __________________ 1967 GMC CM-2500 Camper Cruiser, 351E V-6, NP 435 4 speed, Dana 60, and factory A/C. 2012 GMC K-3500 WT regular cab, 6.0L Vortec, 6L90.

04-29-2014, 08:10 PM	#3
DreamRyder1963 Senior Member Join Date: Jul 2012 Location: Knoxville, TN Posts: 499	Re: GMC 305e Carburator Choice I figured it was unlikely. The more I look at the intake runners the less I think it will work. __________________ 1971 Chevy C10 Cheyenne (sold for Mazda) 1963 Chevy Corvair Pro-Touring Project 2012 Mazda 3 i Sport sedan http://www.dracoautodesigns.com/



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.