[67 ProTouring Catalina]

i do not have the carbs or the intake ifthis is a stupid question i am sorry but does anyone know if you can bolt up 2brrl holleys to a 65'-66' TriPower manifold ?

[Jack Gifford]

Ask Tom V- I think he has done it.

[Tom Vaught]

Originally Posted by pontiac jack

Ask Tom V- I think he has done it.

Yes, I have done it, (a few times).

I did it the first time using a cast iron 1966 Tri-Power Intake set-up with Holley 500 cfm (#4412) carbs (using as was mentioned Offy solid aluminum Holley to Rochester adaptors) in 1984. By then I was working for Ford vs Holley but had three #4412 carbs that were matched on the Holley Wet Flow Stand. I used a Ford 406 Air cleaner with a ribbed aluminum top and a sheet metal base plate. The base plate was not punched for any carb air horn locations. It normally used a single Ford 406 oval air cleaner. I used a 3" tall K&N replacement air filter. I made my own linkage using Ford parts.

While at Ford, in the early days, I met a guy who worked for Chrysler (who was a Dyno Engineer for the 440 6-pack program). He has the actual Dyno carbs used for the dyno power runs for the program. These were vacuum secondary carbs. I bought those carbs and again fabricated linkage to make them work on the cast iron intake. That was the second time. The vacuum carbs looked really cool. Drove nice too.

Ford, at one time, had Holley design up some mechanical "6-pack" carbs that resembled the 440 6-pack carbs for their NASCAR "BOSS 366" Cleveland Engine. They also had Holley design some carbs for the 429 Super Cobra Jet Engine. The program was cancelled after NASCAR would not allow the carb set-up. The carbs were later sold under the Edelbrock brand as race carbs for the 440 "Rat Roaster" 6-pack cross-ram intake. I have a complete set-up of these carbs and a "Rat Roaster" 6-pack cross-ram intake. That deal has not moved for many years.

Currently I have a Barry Grant 6-Shooter aluminum intake (that was ported by Dave Wilcox) that does not need any adaptors. The carbs will bolt right down on the intake and look Holley "factory experimental" with the Mechanical NASCAR Carbs or the 6-pack Vacuum Secondary carbs. That will be the STREET set-up for my 462 Traditional Pontiac engine in my 64 GTO at some point.

All this being said (as historical info), I can help you with your project if you want to go down that path.

Note:

1) Holley carbs are very easy to tune.
2) Gasket kits, jets, etc are available everywhere.
3) The carbs will out-flow all of the other Rochester Tri-Power carbs including the 66 unit.
4) As was said, the OFFY adaptors are still available.
5) You can copy the 6-pack MOPAR fuel line design very easily and have it look "factory"
6) Very nice Ribbed air cleaners are available from O'Brian Truckers. http://www.obrientruckers.com/

(These are currently listed as BG Air Filters but I have been buying them for years before BG made the 6-Shooter set-up. http://www.obrientruckers.com/ecom/i...d93629d2dc.jpg

Make sure that you get the ones for the Holley 6-pack carbs, not the BG carbs, as the air horn shape might be different.

Hope this helps.

Tom Vaught

[67 ProTouring Catalina]

Originally Posted by Tom Vaught

Yes, I have done it, (a few times).

I did it the first time using a cast iron 1966 Tri-Power Intake set-up with Holley 500 cfm (#4412) carbs (using as was mentioned Offy solid aluminum Holley to Rochester adaptors) in 1984. By then I was working for Ford vs Holley but had three #4412 carbs that were matched on the Holley Wet Flow Stand. I used a Ford 406 Air cleaner with a ribbed aluminum top and a sheet metal base plate. The base plate was not punched for any carb air horn locations. It normally used a single Ford 406 oval air cleaner. I used a 3" tall K&N replacement air filter. I made my own linkage using Ford parts.

While at Ford, in the early days, I met a guy who worked for Chrysler (who was a Dyno Engineer for the 440 6-pack program). He has the actual Dyno carbs used for the dyno power runs for the program. These were vacuum secondary carbs. I bought those carbs and again fabricated linkage to make them work on the cast iron intake. That was the second time. The vacuum carbs looked really cool. Drove nice too.

Ford, at one time, had Holley design up some mechanical "6-pack" carbs that resembled the 440 6-pack carbs for their NASCAR "BOSS 366" Cleveland Engine. They also had Holley design some carbs for the 429 Super Cobra Jet Engine. The program was cancelled after NASCAR would not allow the carb set-up. The carbs were later sold under the Edelbrock brand as race carbs for the 440 "Rat Roaster" 6-pack cross-ram intake. I have a complete set-up of these carbs and a "Rat Roaster" 6-pack cross-ram intake. That deal has not moved for many years.

Currently I have a Barry Grant 6-Shooter aluminum intake (that was ported by Dave Wilcox) that does not need any adaptors. The carbs will bolt right down on the intake and look Holley "factory experimental" with the Mechanical NASCAR Carbs or the 6-pack Vacuum Secondary carbs. That will be the STREET set-up for my 462 Traditional Pontiac engine in my 64 GTO at some point.

All this being said (as historical info), I can help you with your project if you want to go down that path.

Note:

1) Holley carbs are very easy to tune.
2) Gasket kits, jets, etc are available everywhere.
3) The carbs will out-flow all of the other Rochester Tri-Power carbs including the 66 unit.
4) As was said, the OFFY adaptors are still available.
5) You can copy the 6-pack MOPAR fuel line design very easily and have it look "factory"
6) Very nice Ribbed air cleaners are available from O'Brian Truckers. http://www.obrientruckers.com/

(These are currently listed as BG Air Filters but I have been buying them for years before BG made the 6-Shooter set-up. http://www.obrientruckers.com/ecom/i...d93629d2dc.jpg

Make sure that you get the ones for the Holley 6-pack carbs, not the BG carbs, as the air horn shape might be different.

Hope this helps.

Tom Vaught

jesus, i guess he was right, you have done this before, cool, so it wasn't a stupid question, woo hoo , do you have any pics of the holleys on the pontiac ? i was considering using the 350cfm holleys, i really dont think i need 1500cfm for a car of this size, how does the unit drive with the holleys comaprd to the 2gc's ? i've never felt the response was all that great with the 2gc's, what are your thoughts on both?

[Jack Gifford]

Two-barrel carbs with vacuum secondaries? You lost me, Tom...

[Old Man Taylor]

Originally Posted by pontiac jack

Two-barrel carbs with vacuum secondaries? You lost me, Tom...

I think he means vacuum operation of the end carburetors.

[camerjeff]

I do not know about Holley 2bbl's, But I know some one that has taken 3 Holley 4bbls, cut them in 1/2 and used the primary side for his Tri power. Alot of work, but he did get great resaults from it, and it looks great also. I will see if he will send me some pic's to post.

[3X24SPD]

Originally Posted by 67 ProTouring Catalina

i do not have the carbs or the intake ifthis is a stupid question i am sorry but does anyone know if you can bolt up 2brrl holleys to a 65'-66' TriPower manifold ?

You can do it, I think Offenhauser still makes the adaptors.

I mocked it up years ago, and IMO, aesthetically they just overpower the whole top end of the Pontiac motor.

I'm a BBC TriPower guy too, and again IMHO, there is nothing better on top of a 427 Corvette motor than the three factory Holleys, but those same carbs just don't look right on a Pontiac motor.

Plus, it's not the carbs you need to replace- the factory Rochesters modified correctly will work just fine supporting 600+ HP while still N/A.

It's the manifold itself that is the choke point.

Compare the Pontiac design to the Chev or Mopar design that uses the Holley 2300's from the factory and you'll see exactly what I mean.

While we're on the subject, I actually just scored the Holy Grail of BBC TriPowers- a complete '67 Corvette 427/435HP factory high rise TriPower setup.

I'm not exaggerating a bit when I say I feel like I just won the lottery...

[Mr_GTO]

Originally Posted by 3X24SPD

You can do it, I think Offenhauser still makes the adaptors.

I mocked it up years ago, and IMO, aesthetically they just overpower the whole top end of the Pontiac motor.

I'm a BBC TriPower guy too, and again IMHO, there is nothing better on top of a 427 Corvette motor than the three factory Holleys, but those same carbs just don't look right on a Pontiac motor.

Plus, it's not the carbs you need to replace- the factory Rochesters modified correctly will work just fine supporting 600+ HP while still N/A.

It's the manifold itself that is the choke point.

Compare the Pontiac design to the Chev or Mopar design that uses the Holley 2300's from the factory and you'll see exactly what I mean.

While we're on the subject, I actually just scored the Holy Grail of BBC TriPowers- a complete '67 Corvette 427/435HP factory high rise TriPower setup.

I'm not exaggerating a bit when I say I feel like I just won the lottery...

What are you going to do with the BBC 435hp setup? Guessing selling it. My old man has a 435hp yellow vert.

[3X24SPD]

Originally Posted by Mr_GTO

What are you going to do with the BBC 435hp setup? Guessing selling it. My old man has a 435hp yellow vert.

Nope. Installing it.

I have a '69 I blast around with the factory 435/427, but that has the low rise factory TriPower under the hood for that body style.

The high rise '67 intake is a sweet piece that is going on another outrageous and heavily modded '74 454 car that has been with me through many iterations of Grand Sport.

This time around it's a savage big block with a lot of compression- since I just happen to know the guy pumping the VP over at the track when I head in to work teching the cars through on friday nights. "Fill 'er up, James..."

Those two cars are a matched set- white with red interior big block 4-speeds with Hooker Sidepipes. Now both will be TriPower as well.

[Tom Vaught]

Here is the link for the air cleaners that fit Ford/ Mopar/ Chevy "D" ring bases.

http://www.obrientruckers.com/ecom/product/search/2671/

Tom Vaught

[Cliff R]

I haven't looked closely at one, but I would imagine the factory intakes could be modified to accept the 2bbl Holley carbs at the flange without an adapter.

Here's a pic of the iron intake I modified to accept Holley 4bbl carbs at the flange. The extra material required was added via NiCi welding rod, then machined flat and tapped for 5/16" threads. Since the holes go into the runners, they are capped off when not in use.

Making up fuel lines is a breeze with a good bender, and all the fittings available these days. We make our own fuel lines for Tri Power Restorations, in lieu of using what's available aftermarket.....Cliff

[Tom Vaught]

Originally Posted by pontiac jack

Two-barrel carbs with vacuum secondaries? You lost me, Tom...

Jack, This is what a Vacuum Secondary 2BBL Holley carburetor Looks like:

The Center carb on the 6-pack has the same vacuum signal pick-up as a normal 780 Holley carb.

The end carbs are connected to the center carb 'signal Port" with vacuum hoses.

The end carbs have a "Kill Bleed" port inside the venturi area (just like the rear barrels of a 780 cfm vacuum carb. The only real difference between a normal 780 vacuum secondary carb and a vacuum secondary 6-pack set-up is that the signal from the center carb opens TWO sets of butterflys vs on set on the 780 carb.

67ProTouringCatalina, These Links have a lot of good info on the Holley "Tri-Power" carburetors:

http://www.ford6v.com/ford6vtech/ford6vtech.htm

http://www.ford6v.com/photo_gallery/photo_gallery.htm

Tom Vaught

ps Yeh! I have worked on a few of them over the years. No one was aware of the sleeved venturi carbs until I mentioned that we designed them that way to make them work right on the center carb of the 429 Super Cobra Jet Engine. Later the owner of the linked site came across a guy who had a "sleeved carb" experimental Tri-power. The last 2 pics are of that carb.

[67 ProTouring Catalina]

now that is some cool looking tripower stuff, i always thought pontiac should have used the holleys, is it true that 2brrls are rated at a different test pressure than a 4brrl carb ? i was told they were rated on a higher test pressure, the 2brrls i mean, do you think this is accurate tom ? if so, how do you compare cfm

[Tom Vaught]

Originally Posted by 67 ProTouring Catalina

is it true that 2brrls are rated at a different test pressure than a 4brrl carb ? i was told they were rated on a higher test pressure, the 2brrls i mean, do you think this is accurate tom ? if so, how do you compare cfm

A 4 BBL Carburetor is tested to a Standard Test Pressure (established before World War II) of 1.5" of Mercury or 20.4" of Water. (The real number is 20.39265029505" of water).

This means that the lower section of the carburetor (after the throttle blades) has a higher suction pressure vs the pressure at the air horn of the carburetor. They would typically use the same type of Water Manometer as a Flow bench used for testing cylinder heads. Cylinder heads are tested at a variety of test pressures depending on the size of the flow bench. 10" of water, 20.4" of water, 25" of water, 28" of water, 42" of water and even 67" of water test pressure.

A 2BBL carburetor has less overall flow area therefore the carburetors were able to be tested on the same machines at a higher suction pressure. That Standard Test Pressure (established before World War II) was 3" of Mercury or 40.8" of Water. (The real number is 40.7853005901" inches of water)

So naturally if you have a higher test pressure used you get a higher flow number.

A "500 cfm 2 BBL" carburetor if tested at 20.4" of water instead of the 40.8" 2 BBL standard would flow about 350 "4 BBL" cfm.

This means that the "6-pack Carburetor Set-up" that has a "350 cfm" center carb and two "500 cfm" outer carbs (when tested at the 4 BBL standard) would flow about 950 "4bbl" cfm, instead of the assumed 1350 cfm posted for the carbs when tested at the "2 bbl" rating.

Yes, the rating is VERY ACCURATE IF YOU USE THE PROPER RATING SYSTEM.

People can play games with "Suction Pressures" when related to cylinder heads.

Super Flow always used 25" of water "suction pressure". Smokey Yunick had some data from dyno testing that said that if he tested his heads at 28" of water a 5% improvement on the flow bench gave him a 5% improvement on the dyno. So a LOT of people now use that number to quote flow numbers. Barry Grant used to use 28" of water "suction pressure" to make his 850 cfm carbs read a higher flow number (1000 cfm) vs the Holley competition's numbers. Holley had to follow suit to sell carbs so the HP carbs are rated 1000 cfm but if you tested them at the pre World War II Holley standard the carb would still be the old stand-by 850 cfm carb.

Hope this helps.

Tom Vaught

[67 ProTouring Catalina]

Originally Posted by Tom Vaught

A 4 BBL Carburetor is tested to a Standard Test Pressure (established before World War II) of 1.5" of Mercury or 20.4" of Water. (The real number is 20.39265029505" of water).

This means that the lower section of the carburetor (after the throttle blades) has a higher suction pressure vs the pressure at the air horn of the carburetor. They would typically use the same type of Water Manometer as a Flow bench used for testing cylinder heads. Cylinder heads are tested at a variety of test pressures depending on the size of the flow bench. 10" of water, 20.4" of water, 25" of water, 28" of water, 42" of water and even 67" of water test pressure.

A 2BBL carburetor has less overall flow area therefore the carburetors were able to be tested on the same machines at a higher suction pressure. That Standard Test Pressure (established before World War II) was 3" of Mercury or 40.8" of Water. (The real number is 40.7853005901" inches of water)

So naturally if you have a higher test pressure used you get a higher flow number.

A "500 cfm 2 BBL" carburetor if tested at 20.4" of water instead of the 40.8" 2 BBL standard would flow about 350 "4 BBL" cfm.

This means that the "6-pack Carburetor Set-up" that has a "350 cfm" center carb and two "500 cfm" outer carbs (when tested at the 4 BBL standard) would flow about 950 "4bbl" cfm, instead of the assumed 1350 cfm posted for the carbs when tested at the "2 bbl" rating.

Yes, the rating is VERY ACCURATE IF YOU USE THE PROPER RATING SYSTEM.

People can play games with "Suction Pressures" when related to cylinder heads.

Super Flow always used 25" of water "suction pressure". Smokey Yunick had some data from dyno testing that said that if he tested his heads at 28" of water a 5% improvement on the flow bench gave him a 5% improvement on the dyno. So a LOT of people now use that number to quote flow numbers. Barry Grant used to use 28" of water "suction pressure" to make his 850 cfm carbs read a higher flow number (1000 cfm) vs the Holley competition's numbers. Holley had to follow suit to sell carbs so the HP carbs are rated 1000 cfm but if you tested them at the pre World War II Holley standard the carb would still be the old stand-by 850 cfm carb.

Hope this helps.

Tom Vaught

holy hell, that was an answer, man i'n really glad i asked what i thought was going to be a stupid question, so would it be safe to say that 3 of the small-bore 2Brrl's would flow around 750cfm ? i would think that would be a better match for many stock type Pontiac engines dont you ? Or no ? thanks for the detailed response by the way

[tom s]

OK,sorry Tom and everyone else!Pontiac plus Holley 2bbls are just wrong!JMHO!Tom

[old66tiger]

Holy cr*p. I learned more in the last 20 minutes of reading than I learned all week. Nice info Tom.

[mrennie]

Hi Tom,

Just wanted to thank you for all the info you provide and for sharing your knowledge with the hobby. I especially appreciate you taking the time to hammer out such detailed responses, as not many of us have access to the info and experience someone working for a car manufacturer would have.

Guys like you, Cliff, Bret, Jim Hand, etc. really make us smarter!

[hurryinhoosier62]

Tom,

I've always wondered why I hadn't seen someone use 2300 series Holleys on a Tri-Power manifold. Now, I have!