Quote:
Originally Posted by Grant Eldridge
According to the NHRA blueprint specs, the '290 small plug heads have a few more more cc's in the ports. Perhaps the small tapered seat plug is located slightly more efficiently in the chamber? I've used the '063, the '215 and now the '290 but never done a back to back test to directly compare. I've never seen or heard of any '280 castings anywhere except in the NHRA guide, do they actually exist?? Let's hear from someone who knows these head castings, I'd also like to learn which are considered the best to use.....
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I also have never heard of a 280 head (maybe a type error). In 1965 you could have 208's, but they were square ports. In 1967 802's were oval port and in 1971-72 you'd have 820 oval port, but they were open chamber. Some time back CHEVY HI-PERFORMANCE magazine had a supplement issue that rated comparatively all production big block heads (may still be able to get it online) I do remember reading that the later model small plug heads, being the 063 and the 290 had slightly larger intake runner volume. The 290 seems to have the highest core value for an oval port and is the hardest to find hardest to find ...there must be a reason. I have found them on 390hp 454's and on 402's and they are the last of that combustion chamber era. That cylinder head made the 454 with the larger bore and stroke over a 396 quite a strong combination. I would say the 290 is the best one to look for.