Technical Questions about Rochester 2 jets for a 3x2 setup

I have 8 total 55-58 carburetors all with small bases, two without idle jets.
I'm looking for tech on these like do they all use powervalves?
I believe I have enough parts to build them. Where can I get mechanical progressive linkage?
I see speedway sells a complete base and linkage kit but those are for 60's- 70's carbs I believe. I have an edelbrock intake also for the small bases.
These are going on a 30 ford coupe.
I'm trying to run and maintain this car on a budget so cost is always a factor
Thanks, Ken

 

Charlie price at vintagespeed.com sells everything that you would need. I have never had any issues with him, neither 10 years ago nor 6 months ago when I dealt with him last… but I know some other users have.

 

well the 2 factory 3x2 set ups that come to mind for linkage/fuel line and other parts would be a 57 J2 Olds and 58 Chevy 348/315hp ran those earlier style 2 barrel carbs in a tri power setup. The swap to the side outlet 2GC was in 1959. Usually the aftermarket linkage setups have you swap the main shaft for a longer unit to put the progressive stuff on the passenger side.

 

Post photos of the two carbs that do not have the idle mixture screws so we can see what you have, they sure sound like factory tri-power carbs.

 

factory fittings and hardware. Since we'er talking 3x2 set up whats the best jet size for the center carb 56? and the two end carbs 47s? Bone stock 67 283 thanks.

 

Here's a 3x2 progressive linkage made out of stock linkage parts. The pedal rod hooks to the ball stud on the center carb.

 

These are the three I got with the olds intake. I'll post the others also.

 

Thank you!

 

Outer carbs need no idle circuits and the butterflies need to seal when closed. You can make your own progressive linkage with some bar stock. Also make sure you have the proper amount of fuel pressure so it doesn't overflow the outer carbs when not it use.

 

Another sources for parts is Ron's Tripowers

TriPower by WhyW8 posted Jan 22, 2025 at 8:33 AM

 

I like your 30 coupe. My first hot rod back in the 60s was a 30 coupe with a 327 and tri-power. It ran very good with .057jets in the center carb and .076 jets in the two end carbs.

 

I used the Speedway base kit with good results, came with thicker fitted throttle blades, front and rear carbs need to have tight fitting "closed" blades, or they will be a vacuum leak.
If your J-2 carbs are rebuildable they could save you the cost of the whole kit, they got the right bases.
Pretty sure progressive linkage kits with the replacement shafts are available.

Norb

 

Thanks! I LOVE your setup.
original bases? I just bought a set of those scoops. What are you using for filters, any screens?

 

I just bought a set of those scoops. What are you using for filters, any screens?

Mine came with very fine SS screens.

 

Thanks
I ran original bases for a while but had problems with them not closing all the way. Purchased new bases from Ron and that solved that problem.
The old school Frog Scoops came with my tri-power set up when i bought it used, the scoops have SS screens surrounded by a rubber seal.
I ordered some filter material and cut out circle shapes and wedged them in between the rubber seal and the SS screen (wedged around perimeter) NOTE: the filter material is wedged in on the top side of the scoops so it cannot get sucked into the carb.
I use K&N filter oil and clean and re-oil the filter material as needed - not as good as a premium quality air filter but better than no filter at all.