Rochester 2bbrl circle track

[Schwien76j]

Needing a guage legal Rochester 2bbrl 2G 500cfm carb built for a circle track application. I have been around this class of racing for a long time and are familiar with all the catalog order junk and “think I know” fly by nighters. About 20 years ago there was a drag race guy outa the Kansas City area building these carbs and they were OUTSTANDING. Day was the last name. Day Motorsports I believe was his racing outfit. He ran these carbs in the Stock drag racing class and knew them better than himself. He is retired now and no longer doing any carbs. I’m looking for someone like that and Needing your help! If you are or know of someone who if prolific in these carbs please let me know. Looking for a super high quality carb and will spend the money for one. Thanks!!

[ProPower engines]

The best 2bbl rochester carbs I have seen were done by Ryan Brown Performance in Alberta Canada.
He is a ST member and I am sure his contact details can be had here.
PM me if you get stuck.

[Walter R. Malik]

The biggest Rochester 2 brls came on 1958 Pontiacs, (they had the large idle air bypass adjustment screw sticking out the front).
I doubt that those venturis were gauged by anyone these days so, what actual measurements are you looking to get...?

[Tuner]

The largest Rochester 2bbl is 1-3/8" venturi x 1-11/16" throttle bore. They came on a lot of engines. The most common (or easiest to find nowadays) are '70 ~ '71 400 cu. in. SBC. All you need to do to one of those is make a .136" N&S, use a tapered nitrophyl float and jet about .073" to .076". Drill the seat, de-burr it with a twist of 400 wet-or-dry, and stake it with a 3/16" ball to qualify the sealing lip. You need the stock three-sided sheet metal baffle around the N&S that is retained by the lid gasket and you might add a baffle to separate the accelerator pump area from the main part of the bowl. There are ridges in the casting to retain a baffle you make with thin piece of brass sheet so it fits from the bottom to the top of the bowl. Cut a little nip off the lower corner toward the front of the bowl to let some fuel get to the pump. Some old school carbs came with the pump baffle. They all came with the three-sided baffle around the inlet but for some stupid reason the commercial sweatshops leave those baffles out when they rebuild them. Set the float seam parallel level with the inverted lid. Carbs I did with this recipe working on the tailgate of my PU in the pits at the track have won a few championships.

[ProPower engines]

Early Olds 394 2bbl I had used a annular type venturi. Seemed it was 1 year only with the 2 bbl carb up here.
It had an 1 11/16" throttle bore but the venturi size looked like it was straight through the same size or maybe a blond 1 smaller on the ID. Several guys had them years ago but they were outlawed after a max venturi rule became more common and easier to get a gauge to check

[Tuner]

Early Olds 394 2bbl I had used a annular type venturi. Seemed it was 1 year only with the 2 bbl carb up here.
It had an 1 11/16" throttle bore but the venturi size looked like it was straight through the same size or maybe a blond 1 smaller on the ID. Several guys had them years ago but they were outlawed after a max venturi rule became more common and easier to get a gauge to check

I call BS on this. Somebody show me this "annular type venturi" Rochester 2G carb. Internet urban lore is all it is. I have been working on carbs since the late 50's and have never seen such as described here. I bet you had to show Sasquatch ID to buy one. There ain't no such thing.

[ProPower engines]

F****KI gotta remember that one thats good.
Its like a Beaumont down south yall never heard of it but its still a Chevelle up here

[rq375]

I bought a box of cores for a 2x3 project and one had this booster in it, not really annular but different from any other I have seen.

[rpmlou]

I have a few of those exact boosters new in a box. I bought a huge box of 2G carbs awhile back, and found a variety of different boosters. I didn't realize there was such a variety of those made back in the day. The boxes have the part number on it if you need it for some reason.

[dannobee]

Guys, I think the OP said "gauge legal." Don't know about your track/class, but when I was racing circle track the techs had gauges for the venturis AND the boosters. If it failed either one, you were out.

[Tuner]

I bought a box of cores for a 2x3 project and one had this booster in it, not really annular but different from any other I have seen.

Nearly every 283 and 327 2G carb used a variation of that metering cluster with the thin brass washer with the holes in the bottom of the booster. Other GM divisions used variations of the brass gizmo too. Some 2G carbs had the flat part where there are no holes in a different clock position location, probably something to do with distribution. Some have holes all around. Some have holes all around on one side and a the other side has the section with no holes. Some have the steel funnel in the center of the booster, some are cast with the small diameter hole at the top of the booster. They have an accurately machined venturi of sorts at the top of the booster leg where the emulsion tube projects into the leg. The clearance from the tip of the emulsion tube to the inside of the tiny venturi is a qualified dimension and listed in the shop manuals which have full carb details of all the bleed and metering orifice sizes, main jet, PVCR, idle jet, size and number of transfer holes or T-slot length and width, needle and seat, etc.

It is amazing the variations in production carburetor calibrations. Anybody who thinks a universal carburetor can make every engine run like it should is out of their ever-lovin' mind.

[Tuner]

I have a few of those exact boosters new in a box. I bought a huge box of 2G carbs awhile back, and found a variety of different boosters. I didn't realize there was such a variety of those made back in the day. The boxes have the part number on it if you need it for some reason.

Well, I'm jealous. Post the number(s), maybe they can be linked to the carb they were made for.

[GM-DR]

Day Automotive----is Tony Schaffer and yes he builds good 2GC's

[rpmlou]

Here is a couple different boosters I've found.

[Brian 92B]

What is the santioning body or rule set where this carb will be used?