tri power intake
Burning Brakes
Joined: Dec 2003
Posts: 1,150
Likes: 154
I've never read of an actual test of someone taking a tri-power off and replacing it with a 4 barrel with time trials to prove it(and I've owned many magazines from as far back as the 60's) some b.s. from magazine writers but that's all.My vette had a750cfm Holley street(HP)and it wasn't as fast.A" trip" has 1050cfm(if I remember correctly).My 59 vette had dual quads and ran great,my 54 jag had multiple "SU's" and ran great and my 55 shoe box with a 348c.i. had trips and ran great so I"ll go with the theory if one is good,two or three are better.
Burning Brakes
Joined: Jul 2016
Posts: 767
Likes: 74
From: Blaine MN
[QUOTE=SteveG75;1594521680]Carbs have been bastardized by removal of the vacuum diaphragms from the end carbs. These were integral to a good driving system. The throttle linkage has been modified to a mechanical secondary linkage bu the end carbs do not have accelerator pumps.
I ran the stock Tripower setup for while on my 496 BBC then I swapped the carbs for a set of Mopar SixPack 4782/4783 carbs that are designed as a mechanical secondary setup. Accelerator pumps and jets (no plates) on all three carbs. Car ran like a monster but I was tired of the smell at idle and the fact that it would want to die on hard braking due to fuel slosh.
So, my ultimate solution is a custom port injected EFI Tripower. Manifold is an Edelbrock dual quad welded and machined for 3 two barrel throttle bodies. FAST XFI 2.0. All work was done by Bruce at F&B Throttle Bodies. This is all under a stock '75 hood with ~1/2" of clearance and filter that is 3/4" taller than stock. If I was using an L-88 hood, we could have used the Dual Quad Air Gap manifold as a basis.
I've drooled over your EFI setup and continue to do so, sweeet. Which Heads are you using and can you share the rest of your internal specs. (Cam, Crank etc.)
I ran the stock Tripower setup for while on my 496 BBC then I swapped the carbs for a set of Mopar SixPack 4782/4783 carbs that are designed as a mechanical secondary setup. Accelerator pumps and jets (no plates) on all three carbs. Car ran like a monster but I was tired of the smell at idle and the fact that it would want to die on hard braking due to fuel slosh.
So, my ultimate solution is a custom port injected EFI Tripower. Manifold is an Edelbrock dual quad welded and machined for 3 two barrel throttle bodies. FAST XFI 2.0. All work was done by Bruce at F&B Throttle Bodies. This is all under a stock '75 hood with ~1/2" of clearance and filter that is 3/4" taller than stock. If I was using an L-88 hood, we could have used the Dual Quad Air Gap manifold as a basis.
I've drooled over your EFI setup and continue to do so, sweeet. Which Heads are you using and can you share the rest of your internal specs. (Cam, Crank etc.)
Racer
Joined: Feb 2016
Posts: 488
Likes: 43
From: Vancouver British Columbia
That is the same manifold that I have. The only way to tell the date is to remove the oil drip pan. For some reason it is under the drip pan on the bottom of the manifold and the rivets must be removed to remove the pan and check the date.
Go figure!?!
Go figure!?!
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
I've never read of an actual test of someone taking a tri-power off and replacing it with a 4 barrel with time trials to prove it(and I've owned many magazines from as far back as the 60's) some b.s. from magazine writers but that's all.My vette had a750cfm Holley street(HP)and it wasn't as fast.A" trip" has 1050cfm(if I remember correctly).My 59 vette had dual quads and ran great,my 54 jag had multiple "SU's" and ran great and my 55 shoe box with a 348c.i. had trips and ran great so I"ll go with the theory if one is good,two or three are better.
I have been around cars and rev heads long enough to let some folks go with what they adhere to so be it...so if you had a car that did better with a tri power than a single carb, i believe you but doesnt change my mind about the tri power in general...
Heres a question for you, if the tri power was a great performer, better than a single carb, why didnt L88s , ZL1s or even LT1s run them.
Why did chevy stop their use,
Why would motion performance remove tri powers and run single carbs for their phase cars that came with et guarantees.
The draw of the tri power is old school cool.
Drifting
Joined: Nov 2016
Posts: 1,964
Likes: 579
From: Pittsburgh PA
the reason multiple carbs were used back in the day was there wasn't a 4 barrel big enough to flow what was needed by these engines.
by the late 60s, that had changed, and the 427 tri power was nothing more than good marketing. wasn't the 69 427 the last time gm put multiple carbs on anything?
a quick good will give you about 300,000+ articles to read on tri power vs 4 barrels.
articles I have read, 3x2 gave up about 20 hp in the upper rpms. most probably never notice that on the street anyway
by the late 60s, that had changed, and the 427 tri power was nothing more than good marketing. wasn't the 69 427 the last time gm put multiple carbs on anything?
a quick good will give you about 300,000+ articles to read on tri power vs 4 barrels.
articles I have read, 3x2 gave up about 20 hp in the upper rpms. most probably never notice that on the street anyway
Race Director
Joined: Jun 2000
Posts: 10,046
Likes: 675
From: FL
[QUOTE=suprspooky;1594523908]
Setup is a 496 BBC. Short block was built by Ron Sporl down in Alabama who does a lot of off-shore powerboat engines. All 4340 forged, internally balanced. Cam is 240/245 @.050" hyd roller, total lift in the 620" range. Heads are Airwolf from Dr. J. Basically, heavily ported Edelbrock RPM heads. Mcleod RST twin disc on 25# Hays flywheel, T56 Magnum close ratio and 3.73 12 bolt rear built using Tom's Diffs components by Gary Ramadie.
It is very streetable with the EFI. Idles at 850 rpm with a little lope. The light flywheel lets the idle wander a little (+/-50 rpm). Redline is set to 6500 rpm for fuel and 6250 for spark. I use 6000 as a shift point.
According to the tuner (and looking at the torque curve), the exhaust starts choking the engine at about 5500 rpm. I could free up some power by cutting the center caps off the STS baffles (but that would make it much louder) or go to a 3" undercar exhaust (wife likes the sidepipes).
I am very happy with out now and it is a great driver. So, it will stay as is.
Carbs have been bastardized by removal of the vacuum diaphragms from the end carbs. These were integral to a good driving system. The throttle linkage has been modified to a mechanical secondary linkage bu the end carbs do not have accelerator pumps.
I ran the stock Tripower setup for while on my 496 BBC then I swapped the carbs for a set of Mopar SixPack 4782/4783 carbs that are designed as a mechanical secondary setup. Accelerator pumps and jets (no plates) on all three carbs. Car ran like a monster but I was tired of the smell at idle and the fact that it would want to die on hard braking due to fuel slosh.
So, my ultimate solution is a custom port injected EFI Tripower. Manifold is an Edelbrock dual quad welded and machined for 3 two barrel throttle bodies. FAST XFI 2.0. All work was done by Bruce at F&B Throttle Bodies. This is all under a stock '75 hood with ~1/2" of clearance and filter that is 3/4" taller than stock. If I was using an L-88 hood, we could have used the Dual Quad Air Gap manifold as a basis.
I've drooled over your EFI setup and continue to do so, sweeet. Which Heads are you using and can you share the rest of your internal specs. (Cam, Crank etc.)
I ran the stock Tripower setup for while on my 496 BBC then I swapped the carbs for a set of Mopar SixPack 4782/4783 carbs that are designed as a mechanical secondary setup. Accelerator pumps and jets (no plates) on all three carbs. Car ran like a monster but I was tired of the smell at idle and the fact that it would want to die on hard braking due to fuel slosh.
So, my ultimate solution is a custom port injected EFI Tripower. Manifold is an Edelbrock dual quad welded and machined for 3 two barrel throttle bodies. FAST XFI 2.0. All work was done by Bruce at F&B Throttle Bodies. This is all under a stock '75 hood with ~1/2" of clearance and filter that is 3/4" taller than stock. If I was using an L-88 hood, we could have used the Dual Quad Air Gap manifold as a basis.
I've drooled over your EFI setup and continue to do so, sweeet. Which Heads are you using and can you share the rest of your internal specs. (Cam, Crank etc.)
It is very streetable with the EFI. Idles at 850 rpm with a little lope. The light flywheel lets the idle wander a little (+/-50 rpm). Redline is set to 6500 rpm for fuel and 6250 for spark. I use 6000 as a shift point.
According to the tuner (and looking at the torque curve), the exhaust starts choking the engine at about 5500 rpm. I could free up some power by cutting the center caps off the STS baffles (but that would make it much louder) or go to a 3" undercar exhaust (wife likes the sidepipes).
I am very happy with out now and it is a great driver. So, it will stay as is.
Team Owner
Joined: Mar 2002
Posts: 44,681
Likes: 1,830
From: Huntsville AL
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Racer
Joined: Apr 2016
Posts: 493
Likes: 65
Burning Brakes
Joined: Dec 2003
Posts: 1,150
Likes: 154
Sorry you missed the articles i have read, have nothing to prove, and won't plan to go track down countless legitemate testing i have read over the years that a single carb outdid the stock chevy tri power, in true tests of many types
I have been around cars and rev heads long enough to let some folks go with what they adhere to so be it...so if you had a car that did better with a tri power than a single carb, i believe you but doesnt change my mind about the tri power in general...
Heres a question for you, if the tri power was a great performer, better than a single carb, why didnt L88s , ZL1s or even LT1s run them.
Why did chevy stop their use,
Why would motion performance remove tri powers and run single carbs for their phase cars that came with et guarantees.
The draw of the tri power is old school cool.
I have been around cars and rev heads long enough to let some folks go with what they adhere to so be it...so if you had a car that did better with a tri power than a single carb, i believe you but doesnt change my mind about the tri power in general...
Heres a question for you, if the tri power was a great performer, better than a single carb, why didnt L88s , ZL1s or even LT1s run them.
Why did chevy stop their use,
Why would motion performance remove tri powers and run single carbs for their phase cars that came with et guarantees.
The draw of the tri power is old school cool.
Race Director
Joined: Mar 2003
Posts: 11,608
Likes: 780
From: Eustis ( Area 51 Bat Cave ) Fl
Road race cares are made for top end and smoothness coming out of a corner,850 or 860cfm was big enough them on top end with there high rise manifold and forced air induction hood.Any race team wants less problems,so a 4 barrel fills the bill.Plus cost concerns probably enters into the equation on G.M.s return,ie,fuel injection performed better than a 4 barrel on a road course so why didn't they make one for the L88?,cost.I just would like to see someone run a well set up 427-435 with slicks and headers thru the quarter mile,then swap over to a 4 barrel, that's what I have never seen.Oh,if you look at a 1970 A.I.M. they have tri power listed then "canceled"
Motions cars that pulled off the tri powers were straight line drag cars yet motion saw tge single carb as better and had a et guarantee to back that up, it would have been cheaper for them to leave the tri power on the then new cars,
Gm already had tri powers it cost more to out source the l88 holly carb, that sounds like you agree was better in that case than the tri power,
Odd that if a chevy bb tri power was such a great performance item why its not found in the aftermarket
I tend to babble, here below is cut and paste of a very unbiased forum post from the qjet guru Lars,
Dont get me wrong if i could afford them i would run them,
Lars:
During my interviews and reseach for tech articles at GM back in the late 70's, I had several discussions with GM design engineers regarding Tripower (aka "Triple Power Pak") versus 4-barrel. Here are the key comments that came from this:
Originally, the muiltiple carb setups (2x4 and 3x2) were used due to the limited cfm capacity of then-available single 4-barrels (since the Rochester 4GC and the Carter AFB were the only things the auto makers had going in the 50s and early 60s). Thus, the Tripower became associated with performance.
With the advent of large-cfm 4-barrels (Holley & Q-Jet), there was no technical justification for multi-carb setups.
Marketing liked Tripowers and could sell a performance image. Tripowers in the late 60s were marketing tools - not engineering performance tools.
A Tripower (3 2-barrel carbs) cannot feed 8 cylinders as uniformly as a single 4-barrel. Given equal cfm flow through a Tripower and a 4-barrel, the 4-barrel actually has the advantage due to more even fuel distribution.
Tripowers utilizing individual air cleaners have severe cfm flow restrictions due to air filter size. Single large air cleaners for the entire setup flow much better than individual air cleaners for each of the carbs.
Tuning is cumbersome due to the inaccessibility of the center and end carb float bowls on the Holley carbs. This makes quick track tuning almost impossible. But Tripowers still look cool and sound great...
During my interviews and reseach for tech articles at GM back in the late 70's, I had several discussions with GM design engineers regarding Tripower (aka "Triple Power Pak") versus 4-barrel. Here are the key comments that came from this:
Originally, the muiltiple carb setups (2x4 and 3x2) were used due to the limited cfm capacity of then-available single 4-barrels (since the Rochester 4GC and the Carter AFB were the only things the auto makers had going in the 50s and early 60s). Thus, the Tripower became associated with performance.
With the advent of large-cfm 4-barrels (Holley & Q-Jet), there was no technical justification for multi-carb setups.
Marketing liked Tripowers and could sell a performance image. Tripowers in the late 60s were marketing tools - not engineering performance tools.
A Tripower (3 2-barrel carbs) cannot feed 8 cylinders as uniformly as a single 4-barrel. Given equal cfm flow through a Tripower and a 4-barrel, the 4-barrel actually has the advantage due to more even fuel distribution.
Tripowers utilizing individual air cleaners have severe cfm flow restrictions due to air filter size. Single large air cleaners for the entire setup flow much better than individual air cleaners for each of the carbs.
Tuning is cumbersome due to the inaccessibility of the center and end carb float bowls on the Holley carbs. This makes quick track tuning almost impossible. But Tripowers still look cool and sound great...
Last edited by The13Bats; Apr 14, 2017 at 07:40 PM.