[carcrazy]

Current engine is 400 cubic inches about 350 horsepower and has a 1962 tripower. It is a 4 speed car with 3.42 gears. The combination seems to be dialed in pretty good at this point. New engine will be installed later summer/early fall. It is a properly coded 11B 62 389 than now has 459 cubic inches. Hydraulic roller cam and in the 500 horsepower range. It has the KRE d port heads and 10.2 compression ratio. I haven't decided on the intake but will likely use a 65 intake for the newer bolt pattern and keep the existing carbs. This should allow me to use the proper 62 tri power air clearer.... instead of the 3 separate air cleaners. The other option would be to use the KRE tri power intake setup for the smaller center carb however I have no idea if tri power air cleaner will fit this combination. In any event, I don't know anything about the current tri power setup other than it works good. If I go with the a 65 intake what changes (if any) should I anticipate making?

[Alen More]

That sounds like a fantastic build! If you go with the '65 intake, ensure your existing carbs fit properly, and verify if the '62 tri-power air cleaner has enough clearance with the KRE heads and increased displacement. You may need to tweak the linkage, fuel lines, and possibly retune the carbs for optimal performance. Additionally, check that your fuel pump and cooling system can handle the increased demands of the more powerful engine. Overall, the '65 intake should work well with some adjustments. Good luck with your project!

[Dick Boneske]

If your Tri-Power ran well with the 400 engine, but you're going to 459 cubic inches and a healthy hydraulic roller, the carbs need to be calibrated to work with that combo. If you provide cam specs, I can guide you through carb calibration, or you can send me the carbs and I'll do the calibration in my shop.

Basicallly , the changes needed are---idle tubes enlarged from .032" now to about .046". Idle bypass restrictors (stock is .043" or .046") to be enlarged to about .052". Center carb jets about .063" End carb jets .071" or .073". Throttle base idle adj. holes enlarged to .078". If the cam is fairly radical, the center carb throttle plates need to have holes to allow idle position to be proper for idle circuit.

Send me the cam specs, and we'll zero in on exact changes needed.

[Kenth]

Dick, .046" idle tubes? I´m sure its a typo and you ment .036".

JMHO

[carcrazy]

Originally Posted by Dick Boneske

If your Tri-Power ran well with the 400 engine, but you're going to 459 cubic inches and a healthy hydraulic roller, the carbs need to be calibrated to work with that combo. If you provide cam specs, I can guide you through carb calibration, or you can send me the carbs and I'll do the calibration in my shop.

Basicallly , the changes needed are---idle tubes enlarged from .032" now to about .046". Idle bypass restrictors (stock is .043" or .046") to be enlarged to about .052". Center carb jets about .063" End carb jets .071" or .073". Throttle base idle adj. holes enlarged to .078". If the cam is fairly radical, the center carb throttle plates need to have holes to allow idle position to be proper for idle circuit.

Send me the cam specs, and we'll zero in on exact changes needed.

Thanks for the info. I may just send them to you after I do a trial fit. Picking up the engine some time this week. Still haven't decided on the KRE intake or 65. Trying to keep it on the stealthy side but would probably pick up a few horses with the KRE intake plus drop quite a bit of weight.

[carcrazy]

Am hoping the 62 air cleaner works....got a lot invested in it....lol!

[b-man]

You should call KRE and ask if the carb spacing is the same as a factory Tri-Power.

Would make a lot more sense if it did for the Rochester style top so reproduction linkage and fuel lines could be utilized.

With the 1965 intake your 1962 big car air cleaner fitting is a slam dunk.

[65 Lamnas]

The spacing of the carbs is the same. Wasson and I fitted up some modified Rochester carbs to one about a year ago for some dyno testing at KRE. We were also concerned with stock linkage and fuel line fitment in case the spacing was changed. Turns out Jeff and company had already taken all that into account and the factory spacing was retained.

[carcrazy]

Good news about the spacing being confirmed. Jeff told me he thought it was spot on. Makes the decision easy.

[Dick Boneske]

Originally Posted by Kenth

Dick, .046" idle tubes? I´m sure its a typo and you ment .036".

JMHO

The OP noted his engine will have a hydraulic roller cam and 459 cubic inches. He's aiming for 500 hp, which means the cam will be fairly radical.

I've restored Tri-Powers on many Pontiac engines. Very few owners retain the factory cams, which changes the requirements for the idle circuit, jetting, and power valve. In this case, the cubic inches will grow from 389 to 459, which also changes the carburetor calibration.

The numbers I posted for idle tubes, idle bypass restrictors, throttle base hole size are not typos. These numbers are based on experience, not conjecture.

[mike w]

Originally Posted by carcrazy

Current engine is 400 cubic inches about 350 horsepower and has a 1962 tripower. It is a 4 speed car with 3.42 gears. The combination seems to be dialed in pretty good at this point. New engine will be installed later summer/early fall. It is a properly coded 11B 62 389 than now has 459 cubic inches. Hydraulic roller cam and in the 500 horsepower range. It has the KRE d port heads and 10.2 compression ratio. I haven't decided on the intake but will likely use a 65 intake for the newer bolt pattern and keep the existing carbs. This should allow me to use the proper 62 tri power air clearer.... instead of the 3 separate air cleaners. The other option would be to use the KRE tri power intake setup for the smaller center carb however I have no idea if tri power air cleaner will fit this combination. In any event, I don't know anything about the current tri power setup other than it works good. If I go with the a 65 intake what changes (if any) should I anticipate making?

I worked with Jeff at KRE and built modified carbs for the Rochester Dyno pull. I can be reached at 309-360-6385 Mike Wasson

[scott06]

Originally Posted by Dick Boneske

If your Tri-Power ran well with the 400 engine, but you're going to 459 cubic inches and a healthy hydraulic roller, the carbs need to be calibrated to work with that combo. If you provide cam specs, I can guide you through carb calibration, or you can send me the carbs and I'll do the calibration in my shop.

Basicallly , the changes needed are---idle tubes enlarged from .032" now to about .046". Idle bypass restrictors (stock is .043" or .046") to be enlarged to about .052". Center carb jets about .063" End carb jets .071" or .073". Throttle base idle adj. holes enlarged to .078". If the cam is fairly radical, the center carb throttle plates need to have holes to allow idle position to be proper for idle circuit.

Send me the cam specs, and we'll zero in on exact changes needed.

Dick - can you please confirm what is meant by idle bypass restrictors? Is that up in the underside of venturi just outboard of the idle tubes? Where the idle fuel mix goes back down to feed the idle mix screws and ports in throttle plate?

I'm doing a 65 389 (.030) w 4.25" stoke for 447 cubes, stock 77 heads, Spotts HCP-01 cam (similar to summit 2802), stock 65 tripower, RA exhaust manifolds so pretty tame ...

thanks

[Kenth]

The fuel is pushed up through the idle tubes, turns up in the nozzle, mixes with air from the upper air bleeds and goes down through the channel restrictions (economizers) and mixes with additional air from the side air bleeds if applicable and then down to the lower air bleeds/transition circuit to low speed and finally down to the holes for the idle mixing screw tips.
Some units also has idle bypass air drilled in the throttleplates.

[scott06]

Originally Posted by Kenth

The fuel is pushed up through the idle tubes, turns up in the nozzle, mixes with air from the upper air bleeds and goes down through the channel restrictions (economizers) and mixes with additional air from the side air bleeds if applicable and then down to the lower air bleeds/transition circuit to low speed and finally down to the holes for the idle mixing screw tips.
Some units also has idle bypass air drilled in the throttleplates.

that's what I thought it was thanks