[STripleduce]

Kev.I,m jetted exactly the same.The curve comes in at 2700 the outers are opening at 4200 or about 1/3 throttle.Checked cups in plunger bore looks tight.If I move the pump slow no shot if fast excelent(by hand with top off).Set on the outer hole it bottoms out too early,but i get a little on inner hole I get nothing(by hand or llinkage)I'm beggining to suspect the check ball in the pump,going to disect tonight.

[This message has been edited by STripleduce (edited 09-08-2000).]

[STripleduce]

My assumption was correct.On the plunger rod at the bottom there is a brass nipple that holds the check ball in place.it had walked out about 50thnds pressed back on all good now.Motor going in tomarow hopfully hit the track next week.I'll keep you posted.Thanx All.

[GTO-relic]

Old thread, easy answer worth posting for reference. These cfm numbers are at 1.5" Hg. pressure drop to compare to 4bbl.

Small middle carbs on all tripower setups are only 196 cfm dry flow rating.

Big end carbs on tripowers are 307 cfm dry flow rating.

Setups with small center carbs are therefore
307+307+196= 810 cfm total.

1966 tripower setups with 3 big carbs are the therefore 307 x 3= 921 cfm total.

Practical approach is the pre-1966 3-2 setup is not a worthwhile bolt on unless you just like and want one, and/or the price is right. Or if it came oem / correct on the car. You can just buy an 850 Holley 4bbl and make the same power or more, with 40 more cfm, and less hassle. Or run an 800cfm Qjet break even on cfm.

The 1966 tripower with 921 cfm at least you're gaining something at WOT. However, the aftermarket is full of 900-925-950 cfm or larger custom Holley type carbs. You must really want that 3-2 to bolt one on.

So there you have it. Tripower is really a labor of love unless it's on a numbers matching or correct for year car. It's not going to make more power than a modern top notch 4bbl. It's eye and ear candy like the street rod / rat rod stuff.
It will add substantial value to a numbers matching or correct restoration.

Wet flow numbers will be less, basically they're
800-900cfm at best.

[KEN CROCIE]

Divide the 2bbl flow #s by 1.414 to get the 1.5" vacuum (4bbl) rating. The flow #s you quoted are directl from Rochester for the 3" vac. 2bbl flow measuring standard. if you add up your flow #s by 1.414 you get 884 cfm

[steve25]

It does not matter that Tripowers can end up with more CARB cfm then the average Q-jet 4bbl that might be used because there air cleaners as I have proven on my flow bench are a larger restriction, like to the tune of 20% even on the smaller end carbs!

If you compare a 8” diameter x 2.5” air cleaner to a 5” x 4” air cleaner they both have the same area yet the 8 x 2.5 will flow more air once placed on a carb.

It’s impossible for even a 389 no less 421 Tripower motor to hit even just 100% VE with its stock air cleaners.

In fact the 66 set with its 3 large carbs does not make as much power as it should over the 65 set up because of the air cleaner limitations.

The basic rule of thumb for air cleaners is that its diameter should be 4 or 5 times it height when possible.

One advantage that the Tripower set up does have is that once then end carbs open up the tuned length of the intake becomes shorter which raises the rpm of peak hp even though the Tripower set up makes less hp then a 4 bbl factory set up.

So basically the peak hp level of a Tripower noses over slower then the 4 bbl.

And here’s more proof that the added two end carbs on a trip set up don’t do what they should in terms of added more hp.

In one of the 2003 issues of HPP mag they covered a build up of a 421 taken up to 439 cid.

The stock heads were ported up to 218 cfm.

It used a 64 trip set up that was converted to use all 3 big carbs.
This required 3 carb spacers to be made because the spacer used for the center carb was also a adapter to get the needed
bolt pattern to take the big center carb.

The manifold was well port matched.

The cam was a good size solid with .515” lift and the compression was 10.3.

A test on just the center carb made a surprising 350 hp.

Then a test with all 3 carbs in play only produced an added 123 hp and shined a bright light on how inefficient a Tripower intake is!

I get such a chuckle when I see folks who have emptied there wallet to place high flowing aftermarket heads under there eye candy Tripower set up.
It’s such a flat out waste!

[Dragncar]

I bet KREs single plane Tri Power fixes a lot of issues with guys trying to make power with 3 carbs.

[KEN CROCIE]

Steve25: I agree with the air cleaner info. There was a GTO convention in my area back about 1990. H-O held an open house, and we featured a dyno test exhibition for the attendees. We had a TriPower something on the dyno with stock air cleaners. The question came up as to whether the K&N filters were better. One of the guys had a set of K&Ns on his car. We put his filters on the dyno engine and picked up 15HP. Good friend John Sawruk was there to witness the test. Point being the stock filters are quite restrictive.

[slowbird]

Originally Posted by steve25

It does not matter that Tripowers can end up with more CARB cfm then the average Q-jet 4bbl that might be used because there air cleaners as I have proven on my flow bench are a larger restriction, like to the tune of 20% even on the smaller end carbs!

If you compare a 8” diameter x 2.5” air cleaner to a 5” x 4” air cleaner they both have the same area yet the 8 x 2.5 will flow more air once placed on a carb.

It’s impossible for even a 389 no less 421 Tripower motor to hit even just 100% VE with its stock air cleaners.

In fact the 66 set with its 3 large carbs does not make as much power as it should over the 65 set up because of the air cleaner limitations.

The basic rule of thumb for air cleaners is that its diameter should be 4 or 5 times it height when possible.

One advantage that the Tripower set up does have is that once then end carbs open up the tuned length of the intake becomes shorter which raises the rpm of peak hp even though the Tripower set up makes less hp then a 4 bbl factory set up.

So basically the peak hp level of a Tripower noses over slower then the 4 bbl.

And here’s more proof that the added two end carbs on a trip set up don’t do what they should in terms of added more hp.

In one of the 2003 issues of HPP mag they covered a build up of a 421 taken up to 439 cid.

The stock heads were ported up to 218 cfm.

It used a 64 trip set up that was converted to use all 3 big carbs.
This required 3 carb spacers to be made because the spacer used for the center carb was also a adapter to get the needed
bolt pattern to take the big center carb.

The manifold was well port matched.

The cam was a good size solid with .515” lift and the compression was 10.3.

A test on just the center carb made a surprising 350 hp.

Then a test with all 3 carbs in play only produced an added 123 hp and shined a bright light on how inefficient a Tripower intake is!

I get such a chuckle when I see folks who have emptied there wallet to place high flowing aftermarket heads under there eye candy Tripower set up.
It’s such a flat out waste!

With porting the 66 will flow 340cfm

[Kenth]

Originally Posted by KEN CROCIE

Steve25: I agree with the air cleaner info. There was a GTO convention in my area back about 1990. H-O held an open house, and we featured a dyno test exhibition for the attendees. We had a TriPower something on the dyno with stock air cleaners. The question came up as to whether the K&N filters were better. One of the guys had a set of K&Ns on his car. We put his filters on the dyno engine and picked up 15HP. Good friend John Sawruk was there to witness the test. Point being the stock filters are quite restrictive.

Was the stock filters compared to K&N the A193C foam filters or the A220C paper filters?
I guess the K&N was the first design thin wall filters?

[steve25]

Ok, but how many Tripower folks are going to blow another 1200 bucks on porting there intake when they have already dumped close to 3K into new heads?

[steve25]

Ken thanks for the info!
A 15 hp gain is not trivial.

[Kenth]

Last year for the GeeToTiger was 1966.
When GM banned the TriPower (for all but the Corvette) the Tiger died.
Then came the GreaT One.

You all know what i mean. The sound of an open Tri-Power at WOT is hard to beat.

[KEN CROCIE]

Filters: Kenth, I believe the paper filters, but not sure. I'll check with Kevin and see if he remembers.

[Skip Fix]

Surprisingly with a ported E head head, intake ,Shaker base /a paper filter did not loose that much cfm to a K&N(from HO Racing of course!)

[Dragncar]

Originally Posted by steve25

Ok, but how many Tripower folks are going to blow another 1200 bucks on porting there intake when they have already dumped close to 3K into new heads?

Answer, these things can flow 400 cfm !

[steve25]

Yes, because there not a duel plane anymore, there a very low rise tunnel ram in essence, and once you buy that now your into buying carbs or a FI / throttle body set up to feed it.

[slowbird]

Originally Posted by steve25

Yes, because there not a duel plane anymore, there a very low rise tunnel ram in essence, and once you buy that now your into buying carbs or a FI / throttle body set up to feed it.

You could use your existing tri-power carbs

[steve25]

Yes you could, but then are you not doing just the opposite in terms of power production in relation to what you got the high flow intake for anyway.

[242177P]

Let's face it, not every person who buys a set of aluminum
heads is chasing after "fully optimized". I'd rather see a trio
of Holley 2300s than some hideous Procomp carb.