Rochesters definitely have advantages over the old Stromberg’s. One of the biggest problems on the Strombergs was using too much fuel pressure, they can only take 2 ½ - 3 PSI without blowing thru the needle and seat.

After looking at the prices for people are asking for 2G Rochesters (especially outboard carbs) I’m not sure you will be saving much over the Strombergs. There may be some cheaper options with the Rochesters however. Often times rebuildable units can be found for a few bucks at swap meets etc. They’re a simple carb to rebuild and even modify for outboard use.

I’ve played with Rochester Tri-Powers since the 70s, you may already know all this stuff, but just in case:

The first thing I’d look at is the carb spacing on the manifold to make sure the Rochesters will physically fit. The Dodge motor is shorter than their Fire Power cousins so that might be an issue.

The Rochesters 2 Gs come in 2 basic flavors, the small base and the large base. You will want the small base version based on you engine displacement (and it’s what the adapters are set up for).

This is the Tri-Power I built and ran on my 354 Hemi for several years. It’s set up with a large base 2G center carb and small base outboard carbs. If you look closely you can tell the center carb (the large base) is physically larger than the outboard carbs. The intake is set up with progressive linkage and the larger center carb is the one the engine runs on the majority of the time. The larger carb was used on this car to improve drivability when only running on the center carb. The linkage is set up so that the outboard carbs don’t open till about 80 MPH when cruising on level ground.


T2 by M Patterson, on Flickr

Generally speaking the majority of small base carbs have the fuel inlets on the side (although there were a few made with front inlets) and the large base units feed from the front. The large base unit shown here has had the original inlet capped and was drill and tapped on the side of the filter housing for a new inlet. I normally don’t run filters in the carburetors, but rather rely on a good in-line filter.

If you go with Rochesters I would recommend 3 small base carbs with side inlets and progressive linkage. If you use Strombergs you could probably get by using stock units with synchronized linkage due to the small CFM of the Strombergs.

T1 by M Patterson, on Flickr

On true Rochester Tri-Power outboard carbs there are no idle or transition circuits nor are there any idle adjustment screws. There is also normally no power enrichment circuit or valve. The lack of idle and transition circuits make it much easier to get a good idle out of the engine (idle adjustments are all handled with the center carb). The idle and transition circuits are in the base plate of the carburetor. Back when I started playing with Tri-Power setups factory outboard carbs were almost impossible to find so I ended up modifying base plates from standard 2G carbs myself. I modify the base plates by soldering the idle and transition passages and idle adjustment screw hole closed. I generally leave the stock power valve operational. The last step is to insure the throttle plates completely close. From the factory many of the throttle plates are not properly centered in the bore. This is solved by loosening the throttle plate screw and centering the plates. On a side note, some of the small base Rochester 2G carbs stopped using screws and went to rivets to secure the plates to the throttle shaft…..I usually stay away from those.

If you want to avoid the hassle of messing with the base plates they still sell outboard 2G base plates separately.

One of the down sides of the Rochester 2Gs is the lack of jets available for them. My experience is that the majority of them came with 48s in them and that actually seems to be a good all around size (although you might want to try 46s if you can find them). I’ve taken this car from 4500 feet where I live to 200 feet back in Illinois and the jetting seems about right…….although I do usually retard the timing a bit when I get back to Illinois.

As far as air filters based on your engine size you can probably get by with the round 4 5/8” units that are popular. I’ve personally found on anything above 325 CI, those air filters seem to choke the engine (with progressive linkage that filter has to handle all the air going to the engine until the outboard carbs open. Years ago I found larger air cleaners for VW powered sand rails. You had a choice of a centered or offset base so I picked some up. They fit well on this setup.


AC 1 by M Patterson, on Flickr

Although my normal go to air cleaner are the repop Ford dual quad/tri-power units.

T3 by M Patterson, on Flickr

One last thought on running a Rochester setup with progressive linkage and the bases without idle circuits. You will have to nail the throttle every once in a while (never been a problem for me LOL). Especially with the crap gas we currently get the gas in the outboard carburetors can get stale and varnish up……opening the end carbs once in a while will ensure they are filled with fresh gas.

Thanks Mike, what you have provided has been helpful. I’m going to start collecting up all the necessary things I’ll need to convert to the Tri power. In the meantime I have the 4 barrel setup on the motor I’ll use for initial fire up and breakin. I can get by using the 4 barrel for awhile while collecting up everything I need for the Tri power. Hell, I still need to find a car to put this motor in.

It used to be the Barry Grant (six shooter) was the guy/system that was the Tri-Power go to for a lot of people. I believe he was bought out years ago however.

When I do a search for Tri-Power, what mostly comes up is E bay and that’s always a crap shoot. I did come across this site, but know nothing about them.

http://hotrodcarbs.com/store/rochester-tri-power-carburetors.html

I ended up selling the little 37 Dodge truck a while back, in part to finance the HEMI/68 Valiant project and to free up shop space for that project.

Wow, I liked that little truck. Did it stay local?


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A man with your experience is always welcome. Real life experience is not something you get out of a book, and some of the on line experience leaves us with more questions then answers.

I was really just joking about not being allowed to hangout on this sub-forum……ya ain’t getting rid of me that easy LOL. I do appreciate the kind words though.

Dart4forte, I’m not sure how comfortable you are with rebuilding a carburetor, but the Rochester 2Gs are about the simplest ones to go thru. You’d asked about a complete kit and I came across this one today.


s-l960 by M Patterson, on Flickr

It’s sold by speedway thru their E bay store. Type in “Universal Rochester 2-Jet 2G Tri-Power 3x2 Carb Kit” on E Bay. Don’t know if there is any price difference between E Bay or their store so I’d check both places. They sell it with and without linkage. The kits are about 450 and 350 respectively. This kit includes the correct base plates for the end carbs and the shafts are extended to move the progressive linkage to the passenger side, along with an extended shaft for the center carb. You still have to provide the 3 rebuildable carbs.

Since almost all of the old mom and pop junk yards are long gone, there are only about 3 sources left for carburetors. The easiest and most expensive would be to order 3 rebuilt carburetors. You can always go E Bay shopping but my experience is the 2Gs you find there are usually way over priced. My favorite source was the swap meets. You always run into the guy who thinks every junk 2G is a tri-power carb and will try to get $50 and up for them…..in most cases you can find the guy who is just trying to clean their shelf off and are a lot more reasonable. Back when I was setting up tri-powers (and the 6X2 on the 37 Dodge) I’d snatch every small base 2G I could find that was $10 or under, and there were a lot of them.

The nice thing about the 2Gs (both large and small base) is now days it’s pretty easy to find the original application for the Carb. Unless it’s a really early carb with a metal number tag, the carburetor number is stamped on the passenger side of the fuel bowl. You can see the numbers on the picture of the Chevy tri-power that shows the fuel lines. Type number into a search engine and usually one of the first results will be the application (division, year and engine displacement).

Most of the Rochester small base carbs you come across will probably be Chevrolet. In most cases the choke on these will be external (a heat stove cast into the intake with a rod running up to the choke plate). These work great for the end carbs but can be problematic to get an automatic choke on. If you’re real lucky you may come across one of these. They were normally found on Pontiac and Oldsmobiles (and even a few Jeeps). On the small base carbs equipped with integral choke they are normally mounted on the top cover (unlike the large base carbs where the choke is normally mounted on the base). Don’t worry if the choke isn’t electric, all it takes to convert it is the correct electric choke which can be bought separately (which I did on the 2 tri-powers shown below).


SB EC by M Patterson, on Flickr


Personally I prefer to run my linkage on the drivers side, that way I don’t have to worry about building it around the fuel lines or choke but that’s me. As I mentioned the linkage on my HEMI tri-power is based on the 60s Ford tri-power. The front slide pulls front carb open and the real slide pulls the back carb open.

The turnbuckles came from the local hardware store and the ends were just flat stock with a slot cut and welded to the threaded end of the turnbuckles.

AC 1 by M Patterson, on Flickr


This is my Small block Chevy tri-power that I’ve run on several engines, from 283 to 383 stroker (I also converted it a large base center carb way back when it was on the 383). I took a different approach for the progressive linkage on this one.


2 by M Patterson, on Flickr


You’ll notice the linkage is mounted high up on the center carb and low on the outboards. This causes the outboard carbs to open quicker and ideally all three carbs reach wide open throttle t the same time. The linkage is completely adjustable so that both end carbs start opening at the same time.

On the Chevy setup the top rod is adjustable to set the tip-in point on the end carbs. The bottom rod is adjustable so that it can be set to drop in the holes when both carbs are closed (too short or long and one or both of the carbs will be slightly open at idle). I could have made it non –adjustable but I found that if the end carbs are removed and put back on there is just enough slop in the carb mounting hole that they might shift from where they had previously been and the rod will need to be adjusted slightly. This linkage was just build out of some old linkage pieces I had laying around and an eye bolt from the hardware store that was the right size for the top rod to slide thru.

For fuel lines the simplest is probably just a fuel block and lengths of fuel line. If you’re trying to replicate an engine built in the 50s this is probably the way to go and they look kind of neat looking with the colored translucent fuel line that was popular back then. One caution on the clear or colored lines though…..most are not rated for ethanol fuel (E10/E15). You can swear up and down you’ll never run anything but not ethanol gas in it, but what are you going to do if our on empty and ethanol is all the station has. The picture was taken the day I swapped over to dual quads so the intake was pretty nasty after a decade of being on the car.


T2 by M Patterson, on Flickr


Personally I do prefer hard-lines, they’re simple to make if you have a good tubing bender and double flare kit. The tubing and fittings are pretty inexpensive. A variety of fuel blocks can be found on E Bay and the price isn’t usually too bad.



T1 by M Patterson, on Flickr


Or you could go the route that Mopar took with dual quads (and as I recall the six pack setup)……a hand full of brass fittings and some pieces of tubing.


3 by M Patterson, on Flickr


You might notice on both setups that between the fuel lines and electric choke it would start getting real crowded on that side if you add the progressive linkage.

A quick word on carburetor kits. I’d stay away from the cheap Amazon rebuild kits. They are absolute junk. Spend the extra money for a good kit from NAPA or similar.

Doing your own work on the carburetors bases, building your own fuel lines and linkage you could probably set up a set of tri-power carbs for under $500. That would include the core carbs, rebuild kits, air cleaner(s) and electric choke.

Anyway this was just a few more thoughts.

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E Trans Control


http://www.e-transcontrol.com/dodge-transmission/

Looks interesting, but how do you get VSS and TPS on a retrofit?