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| | what is a good combination to get 275 H.P. out of a '57 292 using an offy 3 duce intake?any suggestions? thanks, Dave |
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| I think that you have your work cut out for you.
The manifold is fairly restrictive. Consider this article:
http://members.aol.com/yblock/258hpyblock.htm
This is from a 1972 Popular Hot Rodding article. While there are many newer techniques available, consider that other than the intake, this 312 was built with pretty good components by a person who knew what they were doing. As you can see from the article, the .480" lift, 292* cam was not completely mild for a street engine.
This 312 only made 258 hp.
My Little Y Block Page
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| Ok,thanks,I guess optimism is'nt always a good thing .any one using SB chevy valves w/ reduced stem dia. to increase flow?{1.94/1.50}. Dave |
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| | | Supreme Being
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| Further to the comments on the Offy Tri power manifold. In an article in YBM, issue #55 in 2003, Doug Thrasher reviews Y block intakes. The name Offenhauser has a certain ring to it.. Unfortunately, their 3 carb manifold for the engine was an inferior internal design. If you have to have a 3 carb setup, the best is probably the Edelbrock 573 or the similar Fenton intake. Avoid the Offy intake, it's a power robber..
Paul |
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| | | Supreme Being
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| | Dave: I wouldn't mess with the 5/16 stem valves. If you are bent on using the 3-2s, you can't flow enough air to have the valve stem size matter. The small stems wouldn't be effective anyway below probably 8000 rpm, and the 1.5 exhaust valve is .010 smaller than the stock Y valve. You would be much better off using a 1.6 valve and opening up the throat and port to match. John
John - "The Hoosier Hurricane"
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| | thanks,everyone.Ijust got a good look @ the engine I bought.Well it was IN a '57....It's a ECZ block,with C!TE heads and low lift rockers,so the offy probably wont be the only restriction in the intake tract.I plan on putting the 1.54 rockers on .what can I do to help the heads flow some air?I'm not necessarly marriied to the offy I just want a strong running engine.any suggestions?I'm not afraid to spend a little time and money.... Dave |
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| | | Supreme Being
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| | Dave: The C1TE heads are not only small intake valve heads, but low compression. I would recommend you start with a pair of ECZ-C ('56) or ECZ-G, or 5752113 castings. For street use, the common C heads will suffice, the others have slightly larger intake valves. If you want to keep the C1TEs, you can put the 1.780 intake valves in, larger exhaust valves wouldn't hurt. A little porting, especially the exhaust side, also helps. If the cam has not been changed from the '57, it is OK for a street cam, has a smooth idle. If it has been replaced it will probably be the mildest grind the Y Block ever had. John
John - "The Hoosier Hurricane"
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| | I plan on using an ISKY E-300,zero deck block,balanced,maybe having the flywheel lightened,any other little trick I can think of. I guess its time to start searchin'for some better heads. Dave |
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