I am new to the board and interested in some input from the "radical fringe." I have a 69 roadster, 427 with a stock big block hood. I have been very restricted on intake manifold selection with this hood line.

Long story short in my rebuild and dyno test, I ran 3 manifolds, a torker II with spacer, performer rpm and victor jr. The best performer by far was the rpm dual plane. Gained 30 lb ft of torque over both others from 2500 -4300 and about 10 hp more on top at 6200. Was about even from 4300 to 6000 rpm. Of course the problem is an rpm will not fit under my hood.

I ended up using the torker II with a 1/2" spacer which was the most I could do. It was the second best runner in dyno testing as well. All of this made me think about the prospect of running a ported or modified tri power setup to pick back up the low to midrange, but no one seems to have much info on the real peformance of this manifold. Couldn't find anyone who had flow numbers on it or had really optimized it for performance. Engine makes about 550-570 hp depending on the manifold selected above and about 550 lb ft of peak torque at 4300.

Anyone done any real work with this manifold. What is the potential?

 

Last May, Corvette Enthusiast did an 11.5:1 489 buildup using AFR 315 CNC heads. They tested 3 induction systems: Holley Strip Dominator 4150; Edelbrock RPM Air Gap and a modified 67 Tripower. The 4-bbl intakes were tested with a Holley 950 HP carburetor. The results were impressive:

RPM Air Gap w/Holley HP 950: 643 HP @ 6400; 594 lb-ft @ 5100
Vic Jr. w/ Holley HP 950: 641 HP @ 6400; 603 lb-ft @ 5100
Tripower: 655 HP @ 6200; 591 lb-ft @ 5100

Several years back I ran a Tripower on a mild 540 and made 655 HP at the flywheel. The heads and manifold were ported by Bernard Mondello.

I like the look of the Tripower, and with proper tweaking, can be made to run very well. As you know, the 68-69 Tripowers are lower than the 67 unit, and will give up a few HP accordingly. Given the silly price Tripowers command these days, you’ll want to think long and hard before putting one under the knife!

Good luck.

Mark

 

On "Rides" I saw where "Rad rides by Troy" shaves manifolds a few thou when necessary. If that would let the performer fit, why not try it. A wad of alum foil on top of air cleaner will show clearance or lack of. I'm learning a little at a time how to get things to fit that were not meant to. Why leave 30 ft lbs and 10 hp on the table? JMHO

Ricisan

 

Wow, Mark this is really encouraging. I actually get corvette enthusiast, but I don't remember this article. I may have subscribed afterward. Is it available on line? Most people I have ran this buy were very discouraging, including Wilson Manifolds (a big racing manifold modifier) in Ft. Lauderdale.

The buildup you quote is quite similar to mine, although based on power/torque peaks they went with more cam and a little more head. I have ported, oval port, edelbrock rpms that make about 330 cfm at .600 lift. The good news is my slightly less radical setup, will probably see very little penalty with the tripower as peak power was about 6000 rpms. Looks like the tripower lost a little torque and rpm range on the top, but not much.

Who modified the 67 tripower in the article?

 

You read my mind, and I tried that with clay. Unfortunately, it just won't go. About 3/4" too tall. I would need to go with an L88 hood for clearance. The Torker II with a 1/2" spacer leaves 1/4" of hood clearance and that is it.

 

I stand corrected: I re-read the article and they don't say if the Tirpower was modified or not. They claim the intake was from a 67 400HP so it was an oval port intake.

The Holley Strip Dominator might fit under your hood. It fit under my 67 big block hood (w/ L88 airbox). The Vic Jr I'm currently running required an angle mill in order to fit. Bernard Mondello did the port work as well as the angle mill on the Vic Jr intake.

 

I am not familiar with angle milling as opposed to regular milling of a surface. What is the difference and how did this help you! Does this reduce the hight more than regular milling?

Have never run a Holley strip dominator, but I think (I am assuming you have a 67) that you have a little more room to play with than I do. As you pointed out, and I know, the hood clearance on a 69 is less than a 67. But you have me thinking that if I could take about 1/2" out of the rpm air gap it would fit. Tell me about the angle milling vs. regular milling.

Any chance of getting a copy of that article. Would really like to read it . Anyway to email it to me or copying it and mailing it. I would really appreciate it.

 

Holy moly! Just got a look at your vette on your profile. Nice car! 702 RWHP. Jesus. I am definitely talking to the right guy. LOL.

Quoted the wrong message. This was for you ML67.

 

Try to find a '67 manifold & use mech. linkage. They are a lot taller but will easily clear an L-88 hood. There is a Co. making repops but I can't recall the name. You might try the 50 cc REO acc. pumps on the end carbs. I ran several of these in the late 60's & early 70's . They were everywhere & dirt cheap. Everybody wanted a double-pumper Holly. They work GREAT! Gas mileage was pretty good compared to an 850 Holly.

 

If the head is "Rolled Over" say 2 degrees the valve angle changes (becomes less) & fills the cylindar better. Some Pro Stock heads have a 12 degree valve angle, much less than stock. Stock SBC heads are 23 while some Comp Eliminator guys run 15 degrees. When you angle mill the head you have to mill the gasket surface of the intake manifold or the gasket will not seal. It does make a difference on a serious engine.

 

I tried that on a BRODIX single plane that was too tall for the Car I had at the time. It was a Dominator if that matters but it killed the manifold. I took off enough that I got a little bit of the dividing vane. It messed up the carb signal & ran bad. Maybe it was because it was a Dom. but the motor(a really good 510 roller motor) would hardly run. 4 lean plugs & 4 fat ones. Maybe if you just took a small amt.,I don't know, but I won't do it again. 3/4 inch sounds like a lot.

 

A dual plane manifold will not fit under a stock BB hood if it`s a 68 or later. I ran the tri power on my 68 with the L88 and it performed very well. I liked the looks of the carbs and intake. Just be aware that the carbs are vacuum orientated and trying to modify or use a progressive linkage will not be benificial as the two end carbs do not have acellerator pumps. I did go back to the L88 stuff however.........

 

Do you have any idea of the relative power output of the the tri-power versus the L88 dual plane? I would guess the L88 manifold is close to the RPM air gap type setup. I know it works great but I am trying to retain the stock BB hood while picking back up some of the low and mid range of the dual plane without changing hoods. The tri-power seems the only option here without a hood change.

 

67 won't fit under my hood. Would need to go with a 68 or 69 setup to retain the hood. Keep in mind, I know that if I change hoods, this whole discussion is moot as I would just run the RPM air gap that ran great on the dyno. Trying to find some compromise better than my torker II single plane, which gave up some low and mid but was even from about 4000 rpm on up.

 

Did you take all of this off the top of the manifold or mill the bottom and top to get the clearance.

 

It was milled on the top.

 

You might consider the 68-69 tri-power then. I spent considerable time trying to find a manifold that would work under the stock hood & found none. The tri-power would be better than the torker 2.------------ Memory fades with age but on 2 of those tri-power deals I changed the end carbs. I think we used 500cfm Holly racing 2BBL carbs IHRA had classes for 2 bbl cars so Holly made a race carb that was a 2BBL. I recall it took some work to make them fit but they worked Great! They had no vac. stuff on them . They made big power .

 

Thanks for the help and great information.

 

Check out the Barry Grant Six Shooter. They make an oval port big block setup that may clear.

 

Irish,
When you ran the Performer RPM on your vette, what type of air cleaner base did you use and approimately how much room did you lack from closing your hood?