Hello All! I'm having a pickle of a time trying to identify the 2 bbl Rochester carbs in my Tri- Power Setup. I bought a 1951 Chevy Belair kustom not too long ago with a custom built 292. The carbs in question are large bore / base 2-Jets. I do not have an id tag on them unfortunately, and the only numbers I can find are in a circle on the left side on all 3 that state 7032269 I cant find anything on them, and really need to figure out what carb kits I need to get. The center carb has a manual choke, and the inboard and outboard carbs feature no choke or butterfly's. From what I can gather from my own knowledge is these look like Pontiac carbs, but im not sure. I also have zero idea what CFM they are. Anyone have any ideas? any help is appreciated. Thanks in advance!
Not sure why you need rebuild gets, but if it runs like crap you may start by removing those crappy air filters.
with the front and downward fuel inlet on the carb, they are later 60's through the 70's carbs. I would say look for carb kits for 67-69 Camaro's/ Impala's/Nova's, etc with a 2 barrel. So 327ci/210hp or 307's. They ran a 2GV carb
I saw the thread earlier, but didn't get involved as my answer would be unpopular with the OP. But since I have been paged: those appear to be Frankencarbs, they certainly are not tripower carbs. I personally would start with something else for carbs rather than these, but the suggestion in the post above this one may be a place to START looking for kits for these. My guess on year range would be 1966 or 1967. Jon.
Thanks all for the replies! yes these are not original tri carbs. my guess was early Pontiac. the engine runs great with no stumble or hiccups with them, the reason for rebuild is they are are not ethanol tolerant. center leaks around the venturi center mount screw and outboard around baseplate. The reason these carbs were used, is because it has a one off custom hand fab aluminum intake that is a full open plane type.
Over the years I’ve found a kit usually fits many of the 2 GC’s. There were big an small like said above. These may be off Jeeps which were very popular. If you live near a carb shop they could tell which kit. As I remember there were only 3-4 gaskets used even tho there may be 8-10 in the kit. The accelerator pump needs to be the one for the ethanol. The carb shop in Norwalk Ca. I use doesn’t use kits but buys gaskets and pumps in bulk. If you are industrious I’d figure out progressive linkage. I did for our Howard log manifold using 3 Holleys on a 311” GMC.
Since they are not original carbs, any aftermarket kit will work as long as you are close in the year range. All you need is a couple gaskets and accelerator pump.
I'm curious...it looks to me as though they do not have progressive linkage as is typical with V8's. I wonder if you might be able to pick up some driveability and fuel economy if the linkage was set up to operate progressively?
I would leave it as solid linkage. Three carbs on an inline 6 is generally an excellent set-up IF you use solid linkage. Carbs may or may not be too large. Only by testing will you know. Anyone ever see a Jaguar or Austin-Healey 3000 with progressive linkage? As to the kits, be careful with the body to bowl gasket, and the venturi cluster gaskets. The air horn to bowl gaskets are more interchangeable. Also be careful with the fuel inlet valves; a number of different orifices were used. With three carbs, you don't need the largest orifice, which might lead to flooding with driving on the street. To date, the only accelerator pumps I have found to be ethanol-friendly are those from the underside of a cow (crown leather). Jon.
I haven’t because they use sidedrafts for the most part and manifolds with very small equalizer tubes or any equalizers. I’ll go the other way. I’ve never seen an American car with 3 factory down draft carbs not have progressive Linkage. Corvette 6’s were side drafts.
These are the Pontiac tri power guys. I bet Mike can get you the carb parts you need. https://pontiactripower.com/ Phil
Some good info here https://www.carburetor-parts.com/Rochester-Tri-Power_ep_309.html https://c777913.ssl.cf2.rackcdn.com/rochester_2gc_manual.pdf http://oldengine.org/unfaq/leadfoot/qjet1.htm
Thank everyone for the replies and help! Well I finally found the right kit, however I have been duped...... And I feel like an idiot for not realizing it please excuse my inexperience with tri powers, but this is my first time to have this set up. I'm usually a 4bbl guy. It turns out the two outboard carbs were dummies!!! And not even hooked up. Wtf!!?? I started tearing them down and saw only the center was functional. I left the outboards alone and rebuilt the center since it ran fine, and give me time to figure out what to do. The accelerator plunger was bloated and the power valve piston stuck. I rebuilt it and made sure all Venturi holes were not plugged and the engine runs better. BUT.......at around 45-50mph the engine starts to stumble and hesitate. It does not recover till I slow down. I checked timing and all is good. I have an inline electric fuel pump that is rated for 4-5 psi. I checked the fuel pressure by letting it discharge into a jar, but I'm not sure if it's good or bad. Honestly seemed kind of slow. What could cause the stumble? Is is starving the other intake ports for gas since it's not running a full 3x2? Intake vacuum? I'm running a power brake booster off of the back of the center carb. PVC on other port. I'm not sure what to take on to fix this.....
It sounds like you have a fuel volume problem. What you checked wasn't fuel pressure, but volume. Somewhere there is a spec for that. Check for kinked or pinched lines or a stopped up filter. (should be one in the fuel inlet to the carb, may be others in the fuel lines) Also what saltflats said. Those aren't the freest flowing air filters. Pop the center one off and go for a ride. You didn't mention whether or not there was a block off plate under the end carbs. Without them you would be awfully lean. EDIT: In the picture that manifold looks very wide and thin which doesn't give it much cross sectional area. That could be a restriction to the end four cylinders.
Ended up fixing the problem, the electric fuel pump was toasted, and the inline filter from the tank was full of junk and rust. cleaned and fixed all those issues and it runs great now on just the center carb. The gas tank will need replaced, but I haven't got a clue what it came out of. Original tank is long gone, and this one has the filler neck just above the license plate......
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