Not one to assume most things, I'm curious as to the performance differences, if any, btwn the rectangular port 3x2 intake manifolds for the '67 Corvette BB and the later "high rise" type for the '68 and '69 Corvette. Any input would be appreciated. Mike

The '68 and '69 tri-powers were not high-risers. Just the opposite- they are much lower than the '67 because of hood clearance issues on the new '68 body style 'Vette. That's one reason why the '67 stuff is so much more expensive. The '67 manifolds are what you want if performance (not just looks) is a concern.

It seems the oval port tripower manifolds are more expensive in general than the rectangle units also. Apparently fewer were cast. I really dig tripower, and looked into purchasing an oval port tripower manifold, but I never found one for sale at a reasonable price.

I have a '68 oval port tripower intake and carbs that I may run on the 496 in the '65 Malibu. I plan to break the new engine in first, and I still have a little more work to do to the car. I suspect power wise, it will be a step down from the RPM that is currently on the car. If I decide to go through with it, it will be a winter project.

The 67 setups are much better just like a hi-rise compared to the sunken factory manifolds. Every tri-power I ever played with had extremely good low speed throttle response. They can be a pain if you leave the vacuum system for the outboard working to get the opening right but the making of the outboard carbs mech means you must control the throttle opening with your foot (don't punch it when the motor is down in RPMs)

Wes, please, please please post any differences between the RPM and the tripower. There is little documented on the swap. I recall that Wally said a bud of his saw no difference between the winters and trips in a stock class drag car. I'd don't have a correct carb right now to run a comparo. 750 cfm is way too little carb for my motor, and my 850 is lent out.

Slacker, to answer your question, no one has any hard data, but the lower prodiction # 67 stuff is mucho denieros. I opted for the 'cheaper' 69 rect port ( very high production numbers)and use both a 3/8" gasket and 1/2" phenolic spacer to try and get some more height. All I can say is the car isn't a slouch.

Believe it or not still screwin around with finishing mine. Just sorta slowin down in old age. BTW I have BOTH a 67 oval and rectangle 3x2 manifold. Rectangle is on the car now. Also I have sources for more. Yup the 67 ovals are REALLY expensive but the Rectangles are not being given away eather.

Oman

I have a 68 rectangular port with original carbs and original breather. All is in excellant condition (carbs may need rebuilt, sitting 25+ years) all linkage and fuel lines attached.
http://www.chevelles.com/showroom/ccarney69/tripower.JPG

Any idea what this stuff is worth?

$2500 on a good day. $1800 all day. FWIW and it's certainly a W-A-G.

Oman, any idea how much higher the 67s are? with the aforementioned spacers, I can only fit a 3.125" air cleaner under the hood of the 67. By my calc's 3" is minimum to flow 900 cfm. Guess I could get by with 2.875 or 2.75" ( these are K&N's numbers btw).

Thanks for the numbers. What is W-A-G?

Chris

W.A.G. Wild A$$ Guess. I put my 1967 oval port tri-power setup (all date matched) with air cleaner, linkage and fuel lines up on eBay several months back with the "Buy It Now" at $3500.00, the auction only lasted two hours and SOLD!

Dave

WOW!!!!!!

pdq67

Not Chevy powered, but there was a '65 Pontiac GTO, 472CI Pontiac motor/automatic car w/ Tripower in the pits next to me running 11 teens. Not too shabby at all. By the way, the car was complete including interior and exhaust system.

Needless to say, kind of killed the myth for me that TriPower was outdated.

Gene, I'll be sure to post back. I expected to be on the road last month but "life" keeps happening and taking away my car time, and the little free time I have seems to be spent keeping my '59 on the road.

My set-up may not be the best for comparison, given the engine's displacement combined with a low-rise intake. I spoke with some people in the C3 section of the Corvette forum. The consensus seemed to be that the oval tri-power would support my engine, but that I'd be better off with a square port set-up. Have you done a comparison on your car with and without spacers? BTW, you made your own spacers, didn't you? I was discussing this with a friend, and he seemed to think that with the smaller oval ports, and the tall spacers, the mixture would have trouble turning into the runners.

I don't know how much track time I'll be able to get out of this car, since it's a convertible. I may dyno the car before and after the intake swap, subject to my available time and $$$. Another thing that would interfere with a straight A/B test is that I'll be running an HEI (Curved by TC's Von) with the RPM intake, but I'll probably be running a points type distributor with the tri-power.