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This guide is intended to acquaint you with various intake manifolds for Small Block Chevys (SBC) that accept three two-barrel carburetors. This intake system has been a hot-rodding staple since the '50s. Two barrel carburetors were plentiful and cheap; four barrel carburetors were "new technology" and therefore expensive and rare in the early '50's. Aftermarket manifolds were cast to allow multiple two-barrel carbs to be installed on many different engine families, and the car makers noticed the general appeal of the system. Soon many engines were supplied with Original Equipment Manufacturer (OEM) three two-barrel systems. The manufacturers also applied trendy marketing names. In general, GM used the term "Tri-Power"; while Mopar used "Six-Pack" or simply " 6"; Ford called it "6V" with the "V" short for "Venturi".
Chevrolet never released a Tri-Power manifold for the Small Block as a production item. There were some aluminum prototypes made by Winters Foundry; Smokey Yunick tested at least one small-block manifold designed to accept Holley carbs. He was disappointed in the power produced, and no further work was done on that system. Chevrolet did produce Tri-Power systems for the big blocks; the 348 "W" engine got a system with Rochester carbs, while the 427 Mark IV engine from '67 to '69 could be ordered with triple Holleys.
Since there are no Genuine GM Tri-Power manifolds for the Small Block Chevy other than super-rare prototypes; if you want Tri-Power you're going to have to look to the aftermarket. Fortunately, several manifolds are still available new, and two companies are still making 3X2 carb sets. Holley is still producing replacement carbs for the Mopar 340 and 440 engines; although they have discontinued the ones for the Corvette. Barry Grant/Demon is selling 3X2 systems for various engines; at this point they are only selling the complete "kit" which comes with a manifold, carbs, air cleaners, and linkage.
(Sorry--I have NO CONTROL over the size of the photos)
Can you see the vacuum pods denoting the Holley carbs?
Photo supplied by Schurkey
This is a list of all the aftermarket Tri-Power manifolds for SBC that I am aware of. If you know of others, PLEASE contact me--especially if you have photos that I can include in this Guide.
Demon/Barry Grant "Six Shooter"
Edelbrock 5419 (unpolished) and 54191 (polished)
Photo supplied by johnnyfishbone
Weiand (no part number available to me)
Photo supplied by hotrodcoupe32
There is yet another tri-power manifold which fits Holley carburetors. This is sold by Summit, their part number for the manifold alone is SUM-G1922. It is available separately but is primarily sold as part of a "kit" similar to the Barry Grant/Demon 3X2 kits; in that it includes the manifold, three Holley carbs, air cleaners and linkage. The cost for the kit (about $1900) is less than the BG kit, although the BG kits include a really fancy thermostat housing which the Summit kit does not. I examined the manifold at the Summit store in Reno; the casting looked pretty poor. The one I looked at had a casting void (defect) in one of the runners; it looked like it had been repaired on the top side but not filled in "inside" the port. The sales guys claimed the manifold was made for Summit by Holley/Weiand; but there is no info on the box or the manifold itself to show who made it or where it was made. My best guess--which is not verified by the guys I talked to at Summit--is that it's a cheap 'n' evil Communist Chinese casting which may or may not be machined in the USA. The casting has "Z3x2-SBC-01" cast into the area by the distributor opening.
You might also want to look at Cross-ram manifolds for SBC--A primer
GM Small Block 350 Engine Families--A Primer and HEI Ignitions--A primer
If this guide has been helpful, please click the "Yes" box below. If you have suggestions for improvement, please contact me through the "My Messages" feature of eBay by clicking on my user name above and then on "Contact Member".
Entire contents copyright (C) 2007, 2008 Camino3X2 Feel free to LINK to this Guide in your auctions.
Chevrolet never released a Tri-Power manifold for the Small Block as a production item. There were some aluminum prototypes made by Winters Foundry; Smokey Yunick tested at least one small-block manifold designed to accept Holley carbs. He was disappointed in the power produced, and no further work was done on that system. Chevrolet did produce Tri-Power systems for the big blocks; the 348 "W" engine got a system with Rochester carbs, while the 427 Mark IV engine from '67 to '69 could be ordered with triple Holleys.
Since there are no Genuine GM Tri-Power manifolds for the Small Block Chevy other than super-rare prototypes; if you want Tri-Power you're going to have to look to the aftermarket. Fortunately, several manifolds are still available new, and two companies are still making 3X2 carb sets. Holley is still producing replacement carbs for the Mopar 340 and 440 engines; although they have discontinued the ones for the Corvette. Barry Grant/Demon is selling 3X2 systems for various engines; at this point they are only selling the complete "kit" which comes with a manifold, carbs, air cleaners, and linkage.
(Sorry--I have NO CONTROL over the size of the photos)
Can you see the vacuum pods denoting the Holley carbs?
Photo supplied by Schurkey
This is a list of all the aftermarket Tri-Power manifolds for SBC that I am aware of. If you know of others, PLEASE contact me--especially if you have photos that I can include in this Guide.
Demon/Barry Grant "Six Shooter"
Uses three Demon two-barrel carbs; advertised 750 CFM; mechanical secondary operation. The newest 3X2 system--currently sold as a "kit".
Offenhauser 3287Listed in the Offy catalog as a single-plane manifold for '55--'56 265. Available machined for 3-bolt flanges for Ford/Stromberg carbs; or with 4-bolt flanges for small Rochester carbs. This manifold appears to be discontinued.
Offenhauser 3558Listed in the Offy catalog as a single-plane manifold for 283, 327, 350, 400. Also available machined for 3-bolt flanges for Ford or Stromberg carbs, or 4-bolt flanges for small Rochester carbs. Probably still available new from Offy.
Offenhauser 5254Listed in the Offy catalog for 283, 327, 350 (large ports) and accepts large base Rochester carbs. Probably still available new from Offy.
Offenhauser 5893 (Base) 5899 (Top Plate) and 5900 (Linkage kit)This is the Offenhauser clone of the GM Camaro Z-28 cross-ram base, but with a 3X2 top plate. Note that the top plate is configured for WEBER carbs, you won't be able to install Rochester, Holley, or Stromberg carbs. The base is still available from Offy, but the top plate and linkage has been discontinued
Dual-plane. Also known as the C-357-B. Accepts small-base Rochester carbs. Older versions could be machined for Ford/Stromberg 3-bolt pattern. The Rochester version is still available new from Edelbrock. Edelbrock used to sell matching carbs for this manifold, but they have been discontinued.
Fenton (no part number available to me)Appears that it was available with either the 3-bolt or 4-bolt carb mounting flanges.
Photo supplied by johnnyfishbone
Weiand (no part number available to me)
Appears that it was available with either the 3-bolt or 4-bolt carb mounting flanges.
Photo supplied by hotrodcoupe32
There is yet another tri-power manifold which fits Holley carburetors. This is sold by Summit, their part number for the manifold alone is SUM-G1922. It is available separately but is primarily sold as part of a "kit" similar to the Barry Grant/Demon 3X2 kits; in that it includes the manifold, three Holley carbs, air cleaners and linkage. The cost for the kit (about $1900) is less than the BG kit, although the BG kits include a really fancy thermostat housing which the Summit kit does not. I examined the manifold at the Summit store in Reno; the casting looked pretty poor. The one I looked at had a casting void (defect) in one of the runners; it looked like it had been repaired on the top side but not filled in "inside" the port. The sales guys claimed the manifold was made for Summit by Holley/Weiand; but there is no info on the box or the manifold itself to show who made it or where it was made. My best guess--which is not verified by the guys I talked to at Summit--is that it's a cheap 'n' evil Communist Chinese casting which may or may not be machined in the USA. The casting has "Z3x2-SBC-01" cast into the area by the distributor opening.
You might also want to look at Cross-ram manifolds for SBC--A primer
GM Small Block 350 Engine Families--A Primer and HEI Ignitions--A primer
If this guide has been helpful, please click the "Yes" box below. If you have suggestions for improvement, please contact me through the "My Messages" feature of eBay by clicking on my user name above and then on "Contact Member".
Entire contents copyright (C) 2007, 2008 Camino3X2 Feel free to LINK to this Guide in your auctions.
Guide created: 05/23/07 (updated 05/17/12)
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