Rochester 2 Barrel Carbs

[BelAirRoxy]

I had to replace the Rochester 2 barrel carb on my 1966 Bel AIr with a 283. I found a part off a 1965 283 Corvette engine, everything lines up fine and I am planning on installing it soon. However there is a steel tube at the top of the carb that extends into the interior carb about an inch above the jets. It looks like it might attach to something in the vac system, but not sure. Any Ideas what to do with it? What it is for? Could I cap it or leave it blank safely?

Thank you.

[MrPbody]

Okay, first, there were no 2-bbl. Corvettes. I would say "NEVER", but have learned... Maybe an odd one here and there. There MAY have been a few equipped with 3 2-bbls. I don't believe so.

The tube you speak of is there to "draw" the clean air up through the riser pipe that feeds exhaust-temperature heat (not exhaust gas) to the automatic choke "can" on the sde. There's a tube coming up from the intake to the can, with a flared fitting attached. The other tube coming up goes to the tube you speak of with a rubber hose about 1" long connecting them. As vacuum draws a small amount of heated air through the tube to heat the choke spring, "filtered" air is drawn from the air horn (where that tube is) to "fill" the tube, preventing unfiltered air from entering the carb through the vacuum port.

Jim

[MagicRat]

I would suggest not to use the carb. To install it and modify it to fit may mean the choke will not work properly and will not open up as the engine warms up.

If you must install this carb, and if the choke does not work properly, you could cap it off and fabricate a manual choke control. Universal choke control cables are easy to find at tractor/farm supply stores.

However, IMHO it would be a shame to alter such a nice car from its stock condition. I would suggest to repair and rebuild the original carb (if possible) to keep it all-original and working the way GM intended.

[MrPbody]

Roxy,

After rereading your post,it occurred to me, there were no 283 Corvettes in '65, either. SOME 396s, but the vast majority were 327, 300 HP through 375. Where are you getting this information? Sounds awefully fishy to me. MR, do you agree?

I concur with MR about the rebuilding of the original. If you can't find someone local qualified, PM me. I can hook you up.

Jim

[silicon212]

The tube to which you are referring is the float bowl vent. Don't hook anything to it, let it be.

[BelAirRoxy]

Hello all thank you for the advice. I am not concerned about the choke working as the old one never worked properly and I just keep it open at all times, and have no issue starting it to date. The old carb which I would have loved to keep on it for it to be stock has a hirline crack in it so the core is no longer any good. Don't worry though I am planning on rebuliding the engine in the next two years and at that time I will replace this current carb with the original style rochester which I have found everywhere professionally rebuilt and reasonably priced. Just needed a cheap fix until I rebuild the engine Winter 2009-2010.

[Blue Bowtie]

Originally Posted by MrPbody

Okay, first, there were no 2-bbl. Corvettes. I would say "NEVER", but have learned... Maybe an odd one here and there. There MAY have been a few equipped with 3 2-bbls. I don't believe so.

1967 427, 3 Rochester 2GCs, although they were few and far between. Most of the 427s were a 4.

I, too, have learned not to speak in absolutes, having tasted shoe leather more than once.

There's a pretty good diagram HERE

[MrPbody]

Blue Bowtie,

To clear that one up, the '67-'69 400 HP 427 was an "oval port" with the hydraulic cam, 3 Holley 2-bbls. The 435 HP version was a solid lifter/rectangular port version, also with Holleys. After the '66 GTO and a small number of 442s, there were no more Rochester multi-carb setups. That 427 was the only multi-carb engine "mass produced" by GM after '66 (a small number of 2 x 4bbl. setups for certain Chevys), and it went out after '69. The "factory" 3-2bbl. Rocherster setups I've seen for Chevys were on 348s. I'm sure there are other afficiandos that can enlighten us on the small blocks that came with them, but I've only seen them with aftermarket intakes.

Anyone? ... Anyone...?

Jim

[Blue Bowtie]

Come to think of it, they might have been Holley 5100s or something like that. It's been a few years since I've seen the '67 owned by an acquaintance, and what I remember most is that it used two different carbs - One "normal" carb in the middle, and "odd-balls" on the ends.

More shoe leather...