I have a 67ss with a true 67 396 engine with 67 square port/closed chambered heads. The motor is the solid lifter 375hp. version. Does anyone know what carb GM put with this motor in 67. I'm pretty sure it was a Holley and I think it was a single feed but not sure about the cfm. I did the formula that I found in a Holley manual(cu. in/high rpm divided by the constant they supply, etc.) and the final result was that I should be using a 550cfm. Any guidance would be greatly appreciated!

Seems to me a 550 would be a bit light. I'm running a 750 dual feed on my 454, and I don't think it's enough. FWIW.

John

I thought it was the Holley 780?

I thought it was the Holley 780?
Holley 780 with vacuum secondaries just like the one that came stock on my LS6. :)

To the best of my recollection it was a double feed with primary and secondary metering blocks. That said, it was 36 years ago so my memory may be faulty.

I thought it was the Holley 780?

You are correct Wildman. The 67 used a 780 CFM Dual Feed Vacuum secondary carb with Holley List number of #3910. Carb was shared with the 67 Z/28 and Camaro 375HP engines, so original dates are extremely rare and expensive.
Jeff Dotterer
Dated Components
Diamond Restored Judge

Hi MikeyB,

For what it is worth, the GM by the #'s book calls out several depending on the car. They are as follows:
375 w/auto is a 3836
375 manual w/ air is a 3837
375 auto calif w/air is a 3838
375 manual calif w/air is a 3839
375 with none of the above combo is a 3910

Someone please correct me if I am wrong?

Frank