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64-67 Expert
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Discussion Starter #1
I'm beginning a new thread in hopes of generating a discussion and getting some input. I have heard that a well set-up Q-Jet on a stock intake manifold can be made to outperform a Tripower setup on a stock intake. This debate has gone on for decades, but I'm trying to verify the facts. Here's what I know: all things being equal, in my personal experience, the tripower produces more power. I ran the stock Qjet and intake on my '67 GTO (stock 400 with 9:1 compression) and it ran fine. I installed a '66 tripower setup on it and it ran much stronger....felt like a 50 hp gain. I then re-installed the correct intake and carb, and it's been that way ever since. I recently read an old article in HPP where a gent with a '68 GTO with a 428 and a TH400 ran 13.40 or so in the 1/4 mile with his stock Q jet and intake. He made 3 runs, all in the 13.40 range. He then bolted on a '66 tripower, and making no other changes, proceeded to run off three consecutive 12.8's or so. He picked up a full half second. This was on the same day, under the same exact conditions. In my opinion, the tripower flows for cfm, and gets a denser charge of fuel to the cylinders due to the shorter runner lengths on the intake....you have a carb close to every cylinder. I think the confusion comes in because in '67, after the tripower was banned, the magazines were saying that a 4v 400 could beat a 6v 389. They wanted to sell GTO's, and wanted the public to know that the GTO was in no way diminished. It wasn
't: the '67 400 had more cubic inches and far superior cylinder heads and exhaust manifolds. It could beat a 6v 389 with a single 4v. BUT: what if the tripower were bolted on to that '67 400?? The 428 in the test showed a huge improvement. My own '67 showed a huge improvement, though it was a "seat of the pants" measurement, as I did not run the car at the track. It seems that the real racers out there are running a big 4 barrel carb. But, what I want to know is, can a Q-Jet on a stock intake be made to run stronger than a tripower? I'm open to all answers!!! Thanks.
 

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Unless this is a hypothetical question, the first thing that came to my mind is, will the gains of a tri-power outweigh the additional maintenance of a tri-power? I'm assuming a q-jet would be easier to maintain even if it cannot be built to outrun a tri .. Especially, if you're not planning on running it on a track..
 

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64-67 Expert
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Discussion Starter #4
No, GG. This is a "hands on" question. I want to know what other people have experienced/what they're doing. In my experience, I've rebuilt the q-jet on my '67 twice in 120,000 miles and 28 years (original carb, has 242k on it) and I've rebuilt the tripower 0 times in 60,000 miles and 29 years. The tripower is a low maintainence unit, in my experience. I guess what I'm asking is, can a Q-Jet be "worked" to beat a "worked" tripower? (Jets, metering rods, etc.) My experience has been that the tripower produces more power than a q-jet, all else being equal. A buddy just finished the restoration of an HO spec '67 GTO, and he's running a '66 Tripower on it instead of the Q-jet he used to run. He too says it's faster than it wver was with the stock Q-jet.....this should be interesting.
 

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Well now, that's an interesting question. I've always been in the "Qjets are faster" camp, but mostly because "other people" I tend to believe have said so. "They say" that tripowers have fuel distribution problems due to the relatively large area the carbs are spread over and the resulting unequal length intake runners.

Ack-shully though, I 'spose the only way to get a definitive answer would be to run both on the same car at the same track on the same day, with both setups optimized as much as possible for the car, and just see what the clocks have to say about it.

Anybody out there in a position to do that? Or have results from it having been done?

Bear
 

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Discussion Starter #6
Bear, I think I would need to ship you my '66 Tripower so you could dyno that 461 of yours and see what comes up!!! Seriously, though, I'm curious. I'll try to dig up the HPP article and post the actual numbers...I read it again last week. I think a true Q-Jet Guru would know a lot about making power with a Q-Jet as opposed to myself. I know they are excellent, and can move a bunch of mixture. I think a definitive test like you mentioned would answer a few questions, too. (same car, same conditions, just a manifold/carb swap) and run the numbers. Thanks.
 

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In the early 80's with my 68 GTO 400 I got a H-O Power Kit which included instuctions on how to modify my Qudrajet and different springs, jets, rods, etc. This also included a kit for the distributer. I did this to my engine and was very happy with the results. A friend of mine had a tri power intake set up that he was not using. I took off my quad set up and installed the tri set up. What a big difference in power the tri set up had over the quad. I ran it that way for about a year and changed back because I could not afford the fuel it was consuming. At full throttle you can see the gauge drop.
 

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You guys made me think about this, and yes a tri power of equal CFM will outperform a single carb. The middle cylinders are richer than the outers with a single carb set up, as the runners are shorter in the middle, thus compromising both. Now, most cars don't have TBIs, they have MPFI, injector for every cylinder, making every cylinder equal and optimizing power by not compromising anything. Now, the DI-direct injected motor is computer controlled to inject the fuel at the correct time, not just squirting fuel and waiting for the valve to open. GM is getting 305 BHP out of it's stock DI motors, so HP is really in the 400 range, question really answers itself.. Technology is pretty cool.
 

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In the early 80's with my 68 GTO 400 I got a H-O Power Kit which included instuctions on how to modify my Qudrajet and different springs, jets, rods, etc. This also included a kit for the distributer. I did this to my engine and was very happy with the results. A friend of mine had a tri power intake set up that he was not using. I took off my quad set up and installed the tri set up. What a big difference in power the tri set up had over the quad. I ran it that way for about a year and changed back because I could not afford the fuel it was consuming. At full throttle you can see the gauge drop.
I always say mine will pass anything on the road, sept the gas station!! :willy:
 

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I say Qjet. Just pm me, so I can send you my shipping addy for you to send me those crappy tri power set ups. I will recycle them.;)
 

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I replaced my 750cfm 4brl Q-jet on my 66 to the original tri-power and felt a decent gain, I would agree with about 50hp.
 

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Well!..This is certainly good news to me!
I too, have always heard that the Q-jets were the way to go, as far as performance goes. ...much to my dismay, I might add, because I've always loved tri-power.
Looks like I've just added a new sub-project to my goat. I can handle the maintenence.
...I just wanna hear that banshee WAIL!
 

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Are there any special consideration when running a tri power on a two speed auto car with the 3.08 gears.
I want to make the car look stock but dont know how well a reworked stock carb and intake will perforn compared to a holley street advenger 670CFM with Edlebrock performer manifold. I under stand the stock maniford will probaly give me a better low end.
The car does have a after market cam in it. best power seems to be at 3000 - 5200(the shift point)
With this drive train will the Tri Power still be the best option for performance.
 

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64-67 Expert
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Discussion Starter #16
Yes. Tripower came on many GTO's with the two speed and mild gears. It will walk all over your Holley street avenger. And, contrary to misconception, they are low maintainence, dependable units.
 

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Regarding maintenance on the tripowers, I rebuilt my '66 front and rear carbs in '92 and put on a replacement 2bbl Rochester then (wanted to start fresh). Had two problems over the years; 1: some leakage around the top/base flanges, 2: one end carb got gummed up and had to be rebuilt again. I'd never rebuilt carbs before and it was reasonably straightforward. Last year I rebuilt them all again as the engine was pulled for a rear main seal and lifter work. I rebuilt the carbs again, and have a couple points to make there; since my center carb was not quite an original type, I had to order the 3-deuces kit (for the end carbs) and also the specific kit for the replacement carb number (I think it's a later Firebird or other). I didn't mind the extra cost as long as it went right. I bought through Ames, but talked with their supplier. He explained that their kits were very carefully assembled; things like leather cups that work with ethanol mixes, etc (if I remember right). Also, I tied to flatten the carb base to upper horn flanges to avoid leakage by sanding them a bit on a flat glass plate, a trick the garage suggested. The point is, there may be some maintenance quirks to be aware of to avoid problems. So far (only 300-400 miles) they work ok and leakage mess at the flange points is minimal.
 

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Discussion Starter #18
Any induction system will need some initial refurbishment if its 45 years old, be it a single two barrel, 4 barrel, or triple two barell. Once "set up", the tripower is a solid, trouble free unit. Only the middle carb has a choke and idle mixture circuit. The one on my '65 has been on the car since 1965, and I think I kitted the carbs in 1982. They have not been touched since. Yes, they look grungy, but they work great. I have a '66 Tripower setup that sits in my garage for years at a time, and then I'll throw it on an engine and run it....I replaced the center carb in 1979, but never even kitted the outer carbs. It is "ready to bolt on" as we speak. My personal opinion is, if you can run a tripower, do it. You'll love it!!!
 

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I'm a little surprised some say it's trouble free once set up. I've had my car w/the tri power a short time, about 4 years now. The center carb and tri power setup has needed 3-4 adjustments with various things. But when I had the 67 w/the quadrajet, it was serviced once and never again needed work the remaining years I had it. May be just luck...
 

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Discussion Starter #20
Dave, that's funny...My experience has been exactly the opposite of yours. As I've said, I haven't fiddled with my TP for decades, but I've rebuilt/repaired the Q-jet on my '67 maybe 4 times in fewer years. Must be the luck of the draw.....
 
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