what exactly is wrong with 72 cylinder heads that make them prone to detonation with high compression ratio(9or10to1) is it the anti reversion humps in the exhaust ports?
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what exactly is wrong with 72 cylinder heads that make them prone to detonation with high compression ratio(9or10to1) is it the anti reversion humps in the exhaust ports?
The 1972 production year passenger car head for the 429/460 engines is casting number D2VE-AA. This is the only oem cylinder head that is a true, open chamber head. (All 429/460 heads produced before and after this head are closed chamber heads.) Combustion chamber volume on the D2VE head comes in at about 97-100 cc's or so.
Ford abandoned the D0VE head due to emmissions reasons and the D2VE head was their initial answer to lower compression. It's overall performance was less than anticipated and so the very next year Ford came out with yet another head, the D3VE-A2A. That head is more like the D0VE head, in that it too is a closed chamber head but Ford simply lowered the combustion chamber into the head about another .100", thereby getting 97cc's that way.
It seems to be the D2VE's open chamber design that makes them detonation prone/does not work on these engines in a performance application. The closed chamber head allows for the flame front to propagate across the head in a much shorter period of time than the open chamber head, and this translates to more immediate power (torque) and less chance of preignition.
Sure, with enough anti-knock additive, the D2VE won't ping, but you can bet that on the same engine the other heads will require much less octane booster and will show better torque numbers on the dyno.
As far as your speculation on the exhaust port goes: ironically, the 1972 D2VE exhaust port is one of Ford's better 429/460 production iron exhaust prots.
Paul