TONYS68L36

Besides the age old problem of tunning these things is there any other down side to using them. I love the look and am thinking about one for a BB project. What are the limitations to this type of set-up??? My goal is 550 rwhp. Thanks all :D

Alwyn678

Only down side I see is in the gas meter going down and ur wallet getting lighter......Oh yeah watch out for parking on hills (gas Seepage)

a smith

From everything that I have read you will get more HP from the correctly set up four barrel.I love the looks of a three two set-up and would gladly give up a few ponies for the classic look of 2x2x2.

Tominator

Is there a company that sells the set up? :confused:

Jay M

There is a place in ontario CA called The Speed Merchant. He has been working on Corvettes since the '60s. I went to his shop to look at a car he had for sale, and while I was there I noticed that he had a bunch of tri-power setups on the shelf. Back in the '60s people didn't like them because they are so hard to tune, so he replaced them with 4 barrels.

I don't have the number handy, but do a search in the Yahoo yellow pages.

His prices might be a little high, that was the case with the car I looked at.

~Jay

jimduchek

If you want WILD lookin setups, go with Twinnie's four 2bbl sidedraft setup.. that stuff looks awesome. If you want performance, go aftermarket EFI

Jim

KenSny

I had a six-pack on my 66 GTO's 389. Yes it does require a little more time to get everything in sync. But it looks COOL AS HE** and man does it make a nice noise sucking air at WOT.

GDaina

I don't get it. :confused: What is there to tune and get in sync w/the BB tri power units? Just bolt them on, select the vacuum secondary springs, put the springs in, adjust the linkeage. Total time, if you're a dummy, about 30 minutes. If you've done it before, about 10 minutes. That's all there's to it. Nothing complicated.

This thing about parking on a hill. Wish I had a dollar for every time I parked on a hill. If you park on a hill and your gas drains from a tripower, guess what, the same thing will happen to a 4 BBl.

Chuck Harmon

GDaina is right,

I have a set that I have yet to install. Look to be in good conditions, but all gaskets need to be replaced first. The throttle shaft bores are pretty loose, may have to have bushings put in first.

The only down side I se to them is that they don't have jets for the secondaries. just a preset metering block. George, have you had any trouble with the stock set up with yours? Either too rich or too lean?

The cost for a replacement air cleaner assembly is obscene!

While running only the primaries, mileage should be better, but how many can resist using all 6?

Chuck

ML67

I ran a Tripower prior to the 4bbl/single plane setup now on my roller cam 540" 67 coupe. A few differences: The Tripower *was* harder to tune due to the extra pair of idle and main circuits on the end carbs, resulting in 2 metering plates instead of 1 metering block. And this difficulty was largely due to the stock compression fittings of the Tripower compared to my current AN fittings used on the 4-bbl. Also note this application is a bit more aggressive than the factory 427/435, with both a significant increase in HP and decrease in idle vacuum. Adjusting secondary opening rate on the Tripower was a snap. Once dialed in, no problem, but it was not nearly as "friendly" to work on as a single 4-bbl.

Here is a picture of my engine in Tripower trim



As to performance, I dyno'd 655 HP on my 9.7:1 CR 540 on pump gas at the flywheel. I'm now running 10.4:1 CR w/ a cold air L88 hood and single plane, so I can't separate what gains were from the increase in compression, induction and/or cold air. It is undoubtedly stronger in the current setup, although I have not dyno'd it to quantify the difference.

I would expect the mileage to be better w/ the Tripower if you keep out of the secondaries, particularly if you are comparing this to a mechanical secondary 4-bbl.

In summary, I liked the looks of the Tripower better, and once setup, it ran fine. However I do like the added performance I now have w/ the single plane 4-bbl and functional L88 hood. And there is a certain visceral impact the utilitarian L88 setup exudes that the Tripower, for all its intricate glory, did not exhibit.

550 RWHP is not a trivial figure to obtain. This will take a minimum of 700 HP at the flywheel. Jim Moore (427Hotrod) dyno'd his roller cam 540 at 702 HP @ 6000 rpm at the flywheel and recently got 525 HP on a chassis dyno in his 67. He runs a 4-bbl Dominator on a single plane intake.

Good luck with your choice.

Mark




[Modified by ML67, 4:00 PM 8/3/2001]

GDaina

You can get the next size larger metering plates. The number escapes me, but those mothers are expensive. The tight fit between the carbs prevents the use of the 4099 metering block on the rear carb.

I am using the tri power. The looks are great, and when they kick in, it's gangbusters. I know I'm sacrificing ponies, but there's more than enough to handle 98% of the traffic. :D

KenSny

Yeah George, I must be a dummy. It used to take me 20-30 minutes two or three times a year to keep them carbs in tune, but it was worth it.

Oh well, guess since they were original and had not had a rebuild (I bought the car new, and had about 95k on it when I sold it in 86). I guess it was not as fancy, or sophisticated, as the new stuff.

Glad to see technology has advanced.

Flareside

No problems keeping the 3x2 in tune here.

I have also experienced the "hill flood" syndrome (when I first bought the car), but IMO it was caused by a lack of carb maintenance. Since you have two metering plates, leaks are twice as likely as a 4 barrel. If you check/tighten your carbs metering gaskets every few years, I don't think you'll ever see this problem. The center carb metering block isn't as prone to leaks.

GDaina

Ken, just wondering what did you do to warrent all that maintenance? Once I dialed in on the mein jets and the vacuum springs, I never touched it, except once, I had to change out the primary carb's fuel bowl 'cause the inlet threads corroded. Other than that, nothing.

Had a blast back then, used the lightest springs, and went through a tank a night, but then gas was around .75 for Sunoco 260. Now it's called Sunoco 94.

I have to play with the jetting 'cause I'm still running a little lean with the 533. The secondary springs are dialed in, no leaks, economy is so-so if I control the urge to stomp on it. :D I have to call Holley and get the # for the next size larger metering plate.

KenSny

George: like you said, back then I didn't care much about economy (gas mileage) either. The first year I owned the car I went thru 2 sets of Tiger Paws before I got smart and changed to another type of rear tire.

But I never could get a good balance between crusing and all-out stepping on it. It would either bog out of the hole at stop lights, unless I really feathered in the clutch, or it would start to "strangle" at high rpms (almost red line).

I know a coupe of guys that have a 3x2 setup, one even has it on a 265 '56 and it seems to perform very well. If I had the Goat today, I would probably have a tunnel ram and a 2x4 setup on it. But alas....

clem zahrobsky

geo you can drill the plates. what # plates do you have now? holley sends them out with a - 3 plate .076 jet hole and .035 idle hole :chevy