The Stovebolt Site Forums The Shop Area The HiPo Shop Rochester Dual Jet carburetor

Maybe we can discuss some 2-barrel stovebolt carburetion here, without getting our knuckles rapped, or snide remarks being made. The Dual Jet that GM used on V6 and some small displacement V8's like the Olds 260 looks like it could be useful on stovebolt sixes. The Clifford generic "single carb" intake with the right adapter plate looks like it would work well:

cliffordperformance.net/store/ols/products/42-4500wh-chevy-235-intake-manifold

If we ignore the fertilizer Clifford spreads with their undocumented horsepower gain claims, and focus on actual facts, it looks like this manifold could be a test bed for several variations of 2 barrel carbs- - - -Rochester 2G, Stromberg, Dual Jet, etc. I think I'd try to modify the intake to work with an original equipment single exhaust, or maybe an old school split manifold that keeps the OEM heat riser system intact, though!
Jerry

We must have posted at the same time. I will delete my thread.

Is the dual jet with the lopped off secondary casting the same bolt pattern as a regular QJet?

There’s quite a bit of surface area atop a factory 235 manifold. Could a guy just grind out the right footprint, mill a flat surface, and drill/tap some stud holes? I suspect that might work for the earlier Rochester 2 barrels but not the Dualjet.

I agree the Clifford manifold opens up a lot of possibilities. I hate the price and the lack of a mating option to the factory exhaust.

Nope.

That’s a great visual. Never knew all that was going on in there.

OK - did a search on my database. Carbs that were O.E. on Chevrolet sized displacement engines:

261

Carter WCD Buick 263
Rochester 2-GC Chevrolet 265
Stromberg WW Buick 264
Stromberg WW Studebaker 259

235

Carter WCD AMC 232
Stromberg WW Studebaker 233
Holley AA-1 Ford 239

216

Rochester 2-GC Buick, Oldsmobile, Pontiac 215

All of the above are relatively pleniful, not overly expensive, well-documented (well, except for the Rochesters, which are fair on documentation), and parts are readily available.

There were some other Hudson 262, and Kaiser 262, but these are scarce, in demand, and expensive.

Of the above mentioned units, the Carters are the easiest to tune (metering rod technology, replaceable main metering jets, replaceable idle jets, replaceable vacuum springs).
Next would be the Strombergs (replaceable main jets, idle jets, power jet actuators, and power jets)
Then the Holley (replaceable main jets, idle jets, and power jets)
And bringing up the rear would be the Rochesters (replaceable main metering jets and power jets, but fixed idle jets).

The Carters and Strombergs are documented as to sizes of all items mentioned in the preceeding paragraph, plus air bleed, restrictor, and bypass sizes.
The Holleys are documented in all of the above other than power jets, and these are initiation only, not size.
The Rochesters are documented on main jet size only, after that you have to measure.

Jon

Yes, an adapter plate could be made for a QJ manifold that eliminates the big secondary holes and the DJ would bolt right on. With a little creative metal butchery, I'll bet I could mate up a stock exhaust with a real heat riser to that Clifford manifold.
Jerry

I'm only adding my 2 cents to add info to the thread, the 283 in my '57 has the original 2G with the centrifugal/vacuum governor, the truck was available with a 4 bbl also. I put a minor kit in the 2G a few years ago and it has been reliable. The 2G is a manual choke, mine also has a hand throttle, it starts very quickly, the only complaint is a little hot soak trouble and of course great fuel mileage of 5-6 mpg.