Which Carb?

[Quigley]

I see people talking about 500 CFM Holleys on 305s and was wondering if anyone has tried a 350 CFM. According to Holleys chart a 350cfm is recommended for 305 cubes and 4500 RPM. Does anybody have real world experience with this?

[donrm]

I contacted Holley, they told me the 500 was too big for my 351 e. I put the 500 holley on my motor. I have a fresh rebuilt stromberg available. I listened to other people of the site.
They were right, Holley was WRONG!!! donrm 1966 GMC 8' fleetside Cinti. oh

[bigblockv6]

They will tell you that on paper the Holley is too big and use the 350cfm carb but in the real world the Holley 500 really works and the 350cfm version does not do anything at all that's substantial for performance and you end up with less performance than stock. Actually the stock Stromberg wwc carb is around 425 cfm and shares the same size diameter throttle plates as the Holley , the 350cfm carb's bore and throttle plates are much smaller.

[Quigley]

Are you talking about a 305? I would think 305 or 351 would make a difference.I do not know that,but want to know if that is what we are talking about? :headscratch:

[Funky61]

I have a 500 Holley on my 305 and it made a definite difference.

[tommyduncan]

I put a 500 on my 305 also. I was only getting about half throttle and it was still an improvement.
I am now getting full throttle and it really woke it up! I really have no desire to swap out the V6 now.

I hope to rejet(if it even needs it) and fine tune it one of these days to see how much improvement I can get out of it.