CLASS RACER FORUM - View Single Post - 2-barrel Roch Only Questions

oldskool · 10-07-2021, 01:44 PM

For any of you 2-barrel GM racers who have experience with and/or know a lot about Stock racing with 2-barrel Roch combinations, I have questions.

By now, most everybody here knows, I'm a Pontiac Freek. So, what sparked my interest in this subject is the fact that I don't know of a single Pontiac Stocker, with a 350 or larger cube Pontiac engine, that has run a 2-barrel combo in national competition.

IIRC, it was Billy Nees who posted that there are lots of different sizes of the Roch 2-barrel, & most 2-barrel Pontiacs had the small ones, making them bad combos, at current hp factors. I think he also mentioned that Don Himes ran a 2-barrel Pontiac wagon, in a Pure Stock class maybe, many years ago.

Anyhow, there were lots of 350 & 400 cube Pontiacs that came with a 2-barrel Roch. Even a GTO came with one ! And, a few 455's came with one. I bought a '71 wagon 455 that still had one on it, still running.

So, I'm investigating to see if there were any of the 2-barrel Pontiacs, mid-'70's & older, 350 cube & larger, that might have a carb size & hp factor that would make a decent combo for a Stocker build. To make it clear, I am NOT building such a car. I'm investigating the possibilities of a competitive 2-barrel Pontiac combo. Lets confine the year models to '67-'76.

1st possibility I see is a '67 GTO, 255hp 400 cube. hp factor is still 255hp. Don't know if anybody has ever tried to run one, in serious national competition. There is no venturi size listed. But there is a carb number listed. "...2GC-7027061..."

So, for you Roch 2-barrel experts, what is the venturi size of that carb ?

http://www.classracerinfo.com/Engine...8&MAKE=Pontiac

At the current 255hp factor, a '67 GTO would have to run K,L or M Stock. Would need to run mid 12's, or slightly slower, to run under the index. Obviously, the 2-barrel would be the limiting factor. Don't know if that combo could run that quick. What do you 2-barrel experts think ?

I'm not familiar with the popular competitive sbc 2-barrel combos. So, what are the popular years & combos ? What classes are they doing well in ? What is the venturi size for the competitive combo's ? Sorry for all the dummy questions. But I'll have to plead almost complete ignorance of this subject.

10-07-2021, 01:44 PM	#1
oldskool VIP Member Join Date: Dec 2014 Location: The Land of Bayous, Boudin & Crawfish Posts: 1,668 Likes: 223 Liked 747 Times in 362 Posts	2-barrel Roch Only Questions For any of you 2-barrel GM racers who have experience with and/or know a lot about Stock racing with 2-barrel Roch combinations, I have questions. By now, most everybody here knows, I'm a Pontiac Freek. So, what sparked my interest in this subject is the fact that I don't know of a single Pontiac Stocker, with a 350 or larger cube Pontiac engine, that has run a 2-barrel combo in national competition. IIRC, it was Billy Nees who posted that there are lots of different sizes of the Roch 2-barrel, & most 2-barrel Pontiacs had the small ones, making them bad combos, at current hp factors. I think he also mentioned that Don Himes ran a 2-barrel Pontiac wagon, in a Pure Stock class maybe, many years ago. Anyhow, there were lots of 350 & 400 cube Pontiacs that came with a 2-barrel Roch. Even a GTO came with one ! And, a few 455's came with one. I bought a '71 wagon 455 that still had one on it, still running. So, I'm investigating to see if there were any of the 2-barrel Pontiacs, mid-'70's & older, 350 cube & larger, that might have a carb size & hp factor that would make a decent combo for a Stocker build. To make it clear, I am NOT building such a car. I'm investigating the possibilities of a competitive 2-barrel Pontiac combo. Lets confine the year models to '67-'76. 1st possibility I see is a '67 GTO, 255hp 400 cube. hp factor is still 255hp. Don't know if anybody has ever tried to run one, in serious national competition. There is no venturi size listed. But there is a carb number listed. "...2GC-7027061..." So, for you Roch 2-barrel experts, what is the venturi size of that carb ? http://www.classracerinfo.com/Engine...8&MAKE=Pontiac At the current 255hp factor, a '67 GTO would have to run K,L or M Stock. Would need to run mid 12's, or slightly slower, to run under the index. Obviously, the 2-barrel would be the limiting factor. Don't know if that combo could run that quick. What do you 2-barrel experts think ? I'm not familiar with the popular competitive sbc 2-barrel combos. So, what are the popular years & combos ? What classes are they doing well in ? What is the venturi size for the competitive combo's ? Sorry for all the dummy questions. But I'll have to plead almost complete ignorance of this subject. Last edited by oldskool; 10-07-2021 at 01:57 PM.