[CINNAMON111]

HAVE BEEN LOOKING FOR TRI-POWER CARB INFO.
I WOULD LIKE TO KNOW IF THEIR IS A WAY TO CONVERT THE STANDARD 2-JET ROCHESTER CARB TO FIT & WORK AS THE FRONT AND REAR CARBS ON A PONTIAC AND CHEVY INTAKE MANFOLD.

[Dick Boneske]

Yes, std. 2 bbl Rochesters can be made to work on the end carb positions. The complete setups sold by Ames, our host, and others use standard Rochester carbs converted for this purpose. Making those mods to std. carbs requires substantial knowledge if the setup is to function decently. The tricky part is getting the end carb throttle bases to not leak air when closed. The throttle plates on std. carbs do not work well because they are much thinner and don't seal the throttle bores well enough. The throttle shafts on std. 2 bbls. are too short to operate any kind of throttle linkage on the passenger side, so unless Tripower end carb thorttle shafts are used, it would be necessary to fabricate your own special throttle linkage. Aftermarket end carb bases are $90-$100+, so you would have quite a bit of investment in "incorrect" end carb even before you eliminate the power valve, block the idle circuits, and fabricate fuel lines to fit the alternate fuel inlet locations.

Since the end carbs were the same (except for a casting number change from '64 on)from '59-'66 on Pontiacs, why not find some rebuildable end carbs and use them instead of trying to modify std. carbs?

The center carb is not as severe a problem as the end carbs. Any Rochester 2 bbl. of the right base size will work OK if jetted correctly and the idle circuit properly calibrated. Especially on '66 Tripowers, the fuel line location is often exactly like the "correct" '66 center carb.

[65gto69]

You can also get the conversion kit through Speedway Motors. This kit will make you base 2G 2bbl Rochester carbs into front and rear end carbs.

http://www.speedwaymotors.com/Roches...age,22244.html

Here is the link to Stacey David's Gearz from "Speed TV". There are episodes on the right hand side, you can click them in order to watch Stacey talk about and show you how to rebuild the Rochester carbs with the kit from Speedway Motors.

http://staceydavid.com/episodes/tri-powers-six-packs

Mark

[6T5 Cat]

The Speedway kits looks to be for small-base carbs only, which won't fit on the end positions of a Pontiac tripower manifold.

[65gto69]

Originally Posted by 6T5 Cat

The Speedway kits looks to be for small-base carbs only, which won't fit on the end positions of a Pontiac tripower manifold.

Looks like you are correct. I didn't even look at that. That really sucks because I was thinking about getting the kit for my setup, but now that i know it is just for the small base Roch. carbs I can bag that idea.

Could it work for the older Pontiac Tri-Powers from the 50's?

If so it may help those people trying to get a tri-power together for their cars.

Thanks for pointing that out.

Mark

[Cliff R]

I just did a complete Tri-Power for a customer. He originally supplied his own carbs, but they were complete junk, so he located "remanufactured" end carbs, and supplied a kit and a stock center carb to convert it, linkage, and fuel lines, etc.

The conversion parts were excellent, and the only modification needed was to use a different idle speed screw with smaller 10-32 threads.

The "remanufactured" end carburetors were a complete "train wreck". Both leaked and flooded when we put fuel to the entire deal, one had no pump shot at all, the other weak/delayed pump shot.

When I took them apart, there was no spring under one pump, they used poor quality pump seals, jets were used and mangled, one jet was cross-threaded about 1 turn into the casting. There was a TON of slop where the inner pump lever attaches to the shaft, causing a HUGE delay in fuel delivery. Ended up MIG welding it to the shaft.

The end carbs were standard units with Tri Power tops on them, blocked off power valve, and idle screw holes in the baseplates.

End result was good, put better parts in them and new jets.....Cliff

[rohrt]

I had already went down the dead end path of the speedway kits. Where were the remanufacured end carbs source from?

[Cliff R]

Don't know, I didn't supply them, they came in a plain box. They looked nice, zinc/chromated castings and small parts, etc. The linkage and all other parts were fine, but very poor quality "remanufactured" end carbs, typically of what we have seen in that industry for many years.....Cliff

[Zimtok]

Originally Posted by 6T5 Cat

The Speedway kits looks to be for small-base carbs only, which won't fit on the end positions of a Pontiac tripower manifold.

I believe the setup he built is like the 66 tripower where all the carbs used the lager base.

The larger base 2bbl carbs can be found all over the place it is the smaller base center carb of the 65 tripower that is difficult to find.


.

[War eagle]

Originally Posted by CINNAMON111

HAVE BEEN LOOKING FOR TRI-POWER CARB INFO.
I WOULD LIKE TO KNOW IF THEIR IS A WAY TO CONVERT THE STANDARD 2-JET ROCHESTER CARB TO FIT & WORK AS THE FRONT AND REAR CARBS ON A PONTIAC AND CHEVY INTAKE MANFOLD.

Locate Hot Rod Magazine 10/12. Great education on getting those trips to work and the fairly easy work required to convert std Rochester to the trip carbs.

[rohrt]

This one?

http://www.hotrod.com/techarticles/e...32_ford_coupe/

[War eagle]

YUP!!!

[6T5 Cat]

Originally Posted by Zimtok

I believe the setup he built is like the 66 tripower where all the carbs used the lager base.

The larger base 2bbl carbs can be found all over the place it is the smaller base center carb of the 65 tripower that is difficult to find.


.

If you click on the Speedway link and read the specs for the kit you will see the bolt pattern and bore sizes (1.440) are for small base carbs.

[rohrt]

I have still been thinking on the OP question for myself. Found a couple good links on turning 2GC carbs into end carbs. Just confirms what Dick said above.

http://www.clubhotrod.com/shop-talk/...rbs-build.html

http://jalopyjournal.com/forum/showt...9068&showall=1


Doesn't appear to be all that difficult (maybe a PITA but not impossible). All the tips and tricks are explained in the links. The flip side is you would still have a fair amount of money wraped up into a project like that. I have a pretty good lot of 2G carbs but I would still need an intake, and I have not seen a bare 66 intake go for anything under $400. 65 and earlier are much cheaper. Then you would need carb kits for all three, thicker butterfly valves for the ends, progressive linkage, 90 deg fittings (Still not sure if there is room for them) and air cleaners.

There was a 66 setup for 800 on ebay that I'm thinking now was a great deal even if it did need a complete rebuild. What sucks is these things seem to be such a gamble anymore getting this old. One of the links explained that as these carbs age the metal surface can start to flake apart even on internal passages. Another thing I read was how the end carbs could go monthes without being used and start to junk up. Just because you kept your foot out of the gas. I hadn't ever considered that.

If I had a car that origanaly came with a Tri-power I could justify spending the hi-end money to do it right. However just wanting the cool factor may be more trouble then its worth unless you have the intake and the time to tinker with it.

[Willshire]

I have a fair bit of experience in this department. started off with a 4 bbl on my 64, bought an EP4B intake, no go with HEI. Thought what the hell am i doing with an old eddy/carter when i could put a trip on. Ebay'd the intake free delivery-nice!, went to the Pontiac nats and picked up anothersomeone had painted and cleaned up all the casting flash $175 - nice again, but now i have 2! lol. Now i need a set of carbs - ebay - bad choice if you are not informed about pontiac tripowers. Bought a set, $475 with fuel lines and linkage. Oh the were labelled pontiac and showed up chevys from some 70's 2 barrel cars still had the chevy throttle bodies on. wouldn't fit the pontiac intake. back in the box, nastygram what have you (still got em). In my foolishness, back to ebay. this time went and picked them up, 4 hr drive into Michigan. Pontiac end carb bases, good! pontiac repop tops, good!checked em all out, thought i had the right stuff, got home ends would work, center needed a diff base ($525, now im $1400 deep). Bought linkages, fuel lines, pumps, jets etc for these latest carbs.(300) even bought the DVD from Mike Wasson at Pontiac Tripower. Watched it 3 times. Interesting fact for those who dont know - Pontiac tripower carbs have larger venturies than chevy! 1-1/4" center compared to 1-3/32" chev, 1-5/16" outers compared to 1-3/16" chev. The size of the ventury is cast in between the venturies on 65 and earlier centers. I used a socket to determin the diameter of the outers. Finally, i bought a set of 65 trips off a GTO from a local guy ($725) and out of the secoind set and the GTO set i have a great set of trips and a 65 intake just in case i want aluminum heads down the road. So, $2500 to get what i could have got, correct, rebuilt, and set up for under $2,000. Just sayin, let my experience save someone else some $$$$

Happy Canada Day Yesterday!

[dadsformula]

I'm gonna be the bearer of some bad news on this issue. I'm one of those guys that
used the repro end carbs and just about every other possible alternative. These are
the results.

1) Original end Carbs are very simple, but also have thick beveled throttle blades that
are needed to properly seal the Carbs. Without this feature they will have or
quickly develop vac leaks. Get Original Carbs, and the fronts and backs are
different.

2) 68 or 69 Pontiac two barrels are the only good replacements for 66 Centers. Others
can be made to work, but these are the only ones that have all of the needed
features for a 66.

3) 64 and 65 Center Carbs can only be replaced with 59 to 62 E-Carbs or Taxi Carbs
from the same years. They have the correct features more or less. Any other
small based Carb is incorrect or will require major Mods to work.

Original are always the best choice, but if your going to use alternatives, the
above can be made to work well with the least amount of effort. Remember
Pontiac made two barrels for 389, 400 and 455's No other company did so
even if they look workable, the effort to get them calibrated to the large
displacements require extensive work and mods