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Old 11-02-2012, 08:47 AM
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Originally Posted by Camaro_Nut2001 View Post
I have a pair of "461" heads, "041" and another pair of "186" if I don't find a good pair of Vortecs. Out of the three, which do you think would do the best on the 400 with a .030 overbore?
These heads are all similar. Prolly not a 5 hp difference between them as long as the are prepared the same. The 041 is supposed to have a little more meat under the spring seat and is "stealthy" in that it doesn't have the double hump identifier.

Pay attention to the compression ratio- a 64cc chamber on a 400 SBC w/flat tops and a tight quench can exceed 11.5:1- higher than pump gas will allow w/o detonation. A 22cc dished piston will put you at about 9.75:1, the absolute limit I would recommend using iron heads- and even then the cam has to be chosen carefully so the dynamic compression ratio isn't too high.

Static compression ratio
*Interactive JavaScript to Calculate Engine's Compression Ratio (CR)

Dynamic compression ratio
*Dynamic CR
*United Engine & Machine Co. Incorporated

You should CC the heads to be sure that each pair are the same, and that none were milled excessively. Even if they are as cast and never been milled, the chamber volumes can vary from published figures.
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