Thread: Tri-Power Carbs build.

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Originally Posted by Mike P

Rather than go through the self-abuse I've done in the past, I decided to make an adjustment tool from an old flexable carb adjusting screwdriver I had laying around.

I found an old 1/4" drive socket that was the right size (after the screwdriver head on the adjuster had been gound off) was shortened and tack welded to the end of the screwdriver shaft.

The drivers side adjuster was a really tight squeeze so I also shortened the the adjuster screw in addition to removing the screwdriver head.

Works great and will be kept in the tool box in the truck of the 57.

2 of my cars have tri-power and all I did was take a short piece of vacuum hose and fit it onto the idle screws. Now I can adjust the idle by hand. The float bowl hides it so you can't see it unless you're looking.

KB

You can add the 2GC choke housing to any 2G carb(at least the ones I've seen).

You can even add an electric choke unit to it. They originally operated from hot air through a tube to the exhaust manifold.

You need to drill a couple of vacuum passages out to make it work as the factory intended, but the holes are cored when the body is cast and they can be drilled by hand. The threaded holes are usually already tapped.

You will need the housing, the vacuum break piston and it's linkage and the choke shaft. You may need the fast idle linkage too, since I don't know what you have.

I doubt if I run a choke on the set for my T, just for the cleaner look. If you do eleminate the choke, you will need to put a washer under the fast idle cam so that you can tighten it down. Otherwise, it will vibrate out of position and cause your idle to wander.

I'm at work right now, but I can post a few pictures tommorrow of the parts you will need, if you're interested.

Mike

Deleted - Wrong thread

I got a PM a bit ago about the air cleaners I’m using on my tri-power setups so I thought I’d post the response here in case it helps other out.

As I mentioned before I usually don’t like to run the small individual air cleaners on Tri-Powers set up progressively because they usually don’t flow enough and can act as a choke at highway RPM.

My personal preference is usually the Ford style dual quad and Tri-Power type air cleaners from the 60s. PAW makes a knock off in chrome steel and aluminum (the steel one is about $50 and replacement filters used to run about $20. I also see them show up on E Bay occasionally.

On the Hemi in the Plymouth hood clearance was at a premium (even with the hood scoop) so I built the air cleaner as low as possible. The particular air cleaner I ordered was for dual quads, but it really didn’t matter because most of the base was cut away anyway.

First I made sure all the carbs were level at the throats (this was done with the thickness of the adaptor plates I made to convert the manifold to Rochesters and base gaskets. I screwed an air cleaner stud that had been ground to a point on top into each of the carbs. I then took a piece of sheet metal that was large enough and set it on the studs and tapped it LIGHTLY with a small hammer. This left me the marks to center the hole saw on. After I cut the holes I set the air cleaner base (which had already had the center cut out) centered where I wanted it to be and marked the inside then added 3/8” to it ant cut the base so it would fit inside the recess. I applied a little sealer to the 2 pieces and riveted them together.

The arrows point to the 2 dimples I had to put in for clearance for the accelerator pump and choke linkage.


Had I had a bit more clearance I usually add spacers to set the air cleaner up a bit higher like I did on the six pac air cleaner I was originally going to run on the other HEMI. The basic set up and figuring is pretty much the same(only twice as many holes. I used an oversized piece of sheet aluminum for a base on this one. After I was satisfied where the air cleaner would sit, I used the air filter itself to make the outer edge and cut it out then trimmed it with some flexible chrome door edge guard.

The spacers were made from a piece of exhaust tubing that was the right diameter and cut to length. As the spacers were steel and the base aluminum, I made up some simple “L” brackets and riveted them to the base. To hold the base to the engine brackets were made that fit over air cleaner studs in the 4 corner carbs, then 2 studs added in the appropriate places to hold the lid on. You might notice the size of the wing nut I use under the air cleaner lid. That was done on purpose……they are physically to large to go past the carb venturies should one come off.

Mike, Thanks for the explanation & pictures, that will be a project for me soon.
acr

I've got a Rochester base that the idle screw is broken off. What is the best way to get it out?
Thanks, acr

Mike, Is there a way to actually disable the power valve? I know Vintage Speed sells them already disabled.

I talked about this on the first page (h post hat shows the power valve). Normally I jsut cut the rod and remove the spring.

Thanks for replying, yes I read that in the article previously. I was referring to disabling the actual power valve itself & making it a plug. Just curious.

Originally Posted by cffisher

I have an old tool made by Snap -On does the same thing. My kid got it for me probably 20 years ago it has a 1/4" drive on the end and is on about a 45deg. / Not a lot of use for it but when you need it its the best. I think it has like a speed-o cable down thru the center and a knob to turn. Nessity the mother on invention.

I have that tool still in it's plastic case, used it maybe 10 times in 20 years,lol, mostly on K cars iirc.

Great article, I have collected and sold dozens of side inlet rochesters over the years, now I will start hoarding a set.
I had a J2 when I was a kid but it must have had aftermarket linkage. It had a slider with a set screw so you could adjust there the end carbs came in. I wish I had a picture of that.

Also as I read about jet availability, or lack of, I thought about a friend who restores Model As. He solders the jets shut and redrills them to the proper size.

Some really good info here Mike!!!!! Thanks for the post and giving up some of that hard earned education and build methods!!!!! You da man!

Mike a couple that I rebuilt. The ones painted red have .55 on the center and .58 on the secondaries. The plated ones have .50 and .52. I've run both on my sb and they both work good with the red ones liking my cam better.

At one time I had a tap I used to rethread the Rochester 2bbls. so that they could use Holley jets, sure did clear up the jet availability problems!!!!!

Mike,

Just wanted to thank for the great info on the tri power end carb conversion.

I'm putting three Rochester 2gs on a Vintage Speed adapter - three twos to four barrel Edelbrock Performer intake on my 72 Olds Cutlass with a 455. I'm going to use a larger bore 2g for the center and smaller bore modified 2Gs on the ends which thanks to your excellent instructions, I'm confident I can modify myself.

Thanks again for the excellent info.

Bill Lilly

Hell, if it doesn't work, I'll pop the 4 barrel back on.

I know this is an old post,but I'm so happy to have found it.
Mike P, I followed your very nicely detailed instructions, and I have to say ,my low buck tripower now works perfect! I cut the power valve rods in the end carbs, used J-B Weld Epoxy on the idle curcuit holes,and used .048 jets in the center carb. This old thing has never had bottom end power before but enough to turn the tires pretty nice now!
Great article,great help from other fellow rodders, thanks to all!
Brian.........now it's Miller time!