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11-22-2014, 02:22 PM | #13 | |
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Location: Murfreesboro TN
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Re: How many 9 second 396/375 alum head A/S A/SA
Quote:
The GMPP 401 aluminum head is listed as an NHRA accepted replacement part for the early cast iron big block Chevy closed chamber rectangle port head. There is a HP penalty for using the aluminum replacement head. For example, we used them on a 69 Camaro 427/425, and that raised the HP rating from 425 to 435, so we had to add 80 pounds when running them in A/SA. There are certain parts allowed by NHRA as replacements for old castings that are both difficult to find, and expensive to buy. In the case of cylinder heads, a HP penalty is applied, it usually starts at 10HP. In the case of the 401 head, it is not allowing a different engine combination, it is allowing the 401 head to be used as a replacement for the OE head, with a HP penalty applied. The same applies to some heads for other makes. An aluminum replacement head is allowed for certain combinations, and it carries a HP penalty.
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Alan Roehrich 212A G/S |
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