CarburetorsCarb discussion and questions. Upgrading your Third Gen's carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
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I found these in the attic of a friends house when he moved in, and they look GM to me......Anyone got any info on them? Will they fit a 305/350? Can I use just the intake alone or do I have to use the Intake/ heads together? What carbs should I use for them? Any and all info will be greatly appreciated.
Re: Found a Triple Deuce Intake and heads.....WTF?
That is the firing order for an OLD (50s/60s) Oldsmobile. Same as the 4/7 swap, that started on the Chevies a few years back. SBC firing order is 18436572.
Firing order is determined by the cam, not the intake.
Re: Found a Triple Deuce Intake and heads.....WTF?
Quote:
Originally Posted by Stephen
That is the firing order for an OLD (50s/60s) Oldsmobile. Same as the 4/7 swap, that started on the Chevies a few years back. SBC firing order is 18436572.
Firing order is determined by the cam, not the intake.
Oh yeah, no doubt on all of your observations, And I noticed the difference in the firing order, Thats why I posted it. but I had a good feeling it was GM. I posted it to help determine the origin, and compatability with a 3rd gen motor......So my guess is that it wont fit due to it being so OLD correct?
Identification
The early Olds V-8s used a "raised" intake manifold design with a separate valley cover. There was also a small "bug" shield in front of the intake. The later V-8 intake seals directly to the block.
Details
Intake manifolds are cast iron unless otherwise noted.
Casting number and ID are located on top front of manifold, usually on the runners.
ID/ Casting
Code Number Year(s) Application/Notes
563966 '55 or '56 4bbl. Iron.
567930 2bbl. Iron. 571145 '57,'58 371, Tri-carb, 3 2bbl. Easy to spot by the 3 carb holes. Mechanical linkage.
1954 and 1955 324s' have smaller intake ports and valves than the 1956 engines. 1955 and earlier four barrel intake manifolds won't fit a 1956 engine unless you put a dent in the lifter valley cover. 1957 and later cylinder heads will physically bolt on to 1949 to 1956 engines, but the port matchup on intake maniflolds will be off because different cylinder deck heights are used. 1957 and later cylinder heads have larger coumbustion chambers and valves.
J-2 Intake Details
First off the J-2 will have "571145" cast in the front.
Secondly, the throttle plates of the appropriate 2-Jet carbs were small, about the size of quarters, the later 2 barrel throttle plates (and appropriate holes in intake) were visibly larger from about 1965 and after.
Further, this intake will only bolt onto the Oldsmobile 371 CID engine made from 1957-1963 due to clearances with cylinder heads and block.
Further, a special vaccuum linkage was used to allow the end carbs to go from closed to WOT at 68° throttle opening on central carb. Central carb provides all fuel for idle and off-idle!
Lack of this vacc system will require a jury-rigged mechanical linkage, if you can scrape up the carbs at Ye Olde Junque Yardes. There are 371's lying fallow. Just gotta find them!
I have this intake, a 371 lined up, and one of the three carbs rebuilt. I will still need the appropriate jets, and some form of linkage that staggers carb opening to eliminate the bog of both ends opening at once.
The J-2 intake fits 371cid blocks and 1957-58 heads ONLY. Have heard of it being adapted for similar applications, but Karl is reluctant to perform non-reversible operations on antiques.
The J-2 intake is a dual-plane intake that used a vacuum-actuated linkage. The center carb provided all idle and off-idle. At a centre carb throttle plate angle of something like 68' (degrees) the vacuum linkage would actuate, and open the end carbs, which operate at WOT only.
The linkage, if complete, is worth more than the bare intake, but probably not as much as a set of correct end carburetors. Not to mention air cleaners, or correct Air cleaner shroud (covered all three).
2GC uses an integral choke, while the 2GV uses a vacuum-break choke. The choke is actuated by a small diaphagm connected to steel tubing that disappears in the area of the exhaust manifold.
Not positive about functionality/routing of tubing.
The Original J-2 carbs are 2x2G (ends) and 2GC (center). These are, again, the small throttle plate variety.
[ Thanks to Karl Aune, Joe Padavano, J2RKT@aol.com, Ryan, Scott Clark for this information ]
Port Sizes
Intake Length Width Area (approx.)
J-2 1.88" 1.19" 2.23"
