[MidnightAuto]

Thanks for the off on pics Dick - but I think I saw them in that other thread I posted that was yours several years back. The manifold looked great. I am not a welder, and if I can make a couple choices to avoid that type of fabrication for now, that would be ideal. Let's see.

Dragncar I found that site as well. Looked interesting, but seemed like that maybe never came to pass. I'll try the number and let you guys know, but if no one has any history with that manifold, I probably would not want to be the first...

[Region Warrior]

Its all good PJ1959.
Never got into the technical side of engineering. Not enough patience.
Understand what your saying.
My buddy is rated Job class 21 machinist. Worked in speed shop from HS(1976) till retiring from severe back injury 2 years ago.
Soaks up every bit of knowledge like a sponge. Probly attended every Reher Morrison class. Knows them by 1st name.

Anyhow.
From my messing with a 66 tri pwr back in the late 80s on my 455/12 heads/744 cam, besides rejeting, 1/2 spacers helped more the I thought would.
And although the 3 chrome a/cleaners look cool, the big 1 pc bath tub makes more power.

[Region Warrior]

Originally Posted by Dragncar

Has anyone ever seen one of these on a running car ?
Not sure if they ever were made. But a big high flowing single plane with 3 deuces might have been cool with ported aluminum heads would be cool.
https://headsandmanifolds.wordpress.com/

I don't think it work to well with original carbs.
Maybe with larger hollys?
Would really liked to try factory high rise version.

[Dick Boneske]

Originally Posted by ponjohn

What carbs?

'66 Tri-Power carbs. Dan Whitmore had removed the air cleaner webs and used jets in the .075" range. I don't know any more details.

I have enlarged venturi holes on end carbs from 1.375" to 1.415". This can be done without breaking through the casting walls.

The stock '66 center carb has venturi's sized at 1.188". There are many Rochester 2G's that have larger venturi's than the stock "575" carb. Some are larger than the end carbs.

I'm sure there have been many words written about the Holley 4412 vs. the Rochester 2G, but I'm not aware of anyone campaigning a Pontiac with three Holley's vs. the Rochester carbs. If, as many have said, the manifold is the limiting factor, why bother to change to Holley carbs on a Pontiac Tri-Power setup?

[MidnightAuto]

Well here is an update. My kre heads arrived today. 290 cfm port-that’s as big as Jeff said the tripower intake could work with. That’s a 60243 cam as well. So I’m excited to get this together and will report back on progress.

[steve25]

Good news to see and hear!

I would like to in a way reinforce what is said in post 64 about bigger carbs.
Duel plane intakes especially when used with hot street Cams and higher flowing heads react very well to greater over Carb size then is normally considered too much.

The problem with the Tripower set up when reworking the plenum , runners and hogging out the end Carbs to a bigger throttle bore size is that all too soon you you have moved the flow restriction to being at the minuscule air cleaner size used!

If anyone is serious about breaking the 560 hp level with a tripower set up, then it’s time for a custom made air cleaner and flow bench time!

[MidnightAuto]

Thanks Steve. I hear u. I’ll be pleased with 450 but won’t have a dyno to know for sure.

[Tom Vaught]

I left my two Performance Years Aluminum 1966 Pontiac Tri-Powers as received. No porting work done.

I had Dave Wilcox port my Barry Grant 6 Shooter Pontiac Tri-Power intake with Holley carbs.
It flows a lot more vs a stock aluminum PY intake. Lots of money spent too.

But I can run the largest CFM Holley 2-BBLs with this ported intake.
The Barry Grant intakes are extremely rare (if you can find the 3rd casting run intake).
The first two runs had casting issues and would take a bunch of welding to get close to the ability to
actually install the B Grant intake on a pontiac head.

Tom V.