sorry i meant to say that the piston stays at TDC longer but that's not necessarily saying that the cam and valve train are, i also didn't say that a long rod had any affect at all on DCR i was talking about the cam and the rest of the combo. also long rods do not require a higher octane fuel, in fact they require a lower octane fuel that is one of the advantages, you can run a higher compression ratio and use a lower octane fuel than the same engine with a shorter rod. i don't where you heard that a long rod makes an engine more prone to detonation but it's wrong, totally incorrect, an engine that is burning the fuel more efficiently is less likely to detonate. a long rod does not create a hotter combustion chamber it creates a more efficient one. also the long rod doesn't create a slower moving piston, it actually moves just as fast as a shorter rod because you're not changing the stroke, it just stays at the top and bottom of the stroke longer piston speed in the cylinder is still the same. it may be moving a tiny bit slower from full speed to a dead stop and from a dead stop to full speed but in reality that's where the main advantage comes from.
i'm not sure where you got your info that a long rod motor is prone to detonate from but it's flat out wrong. also, with piston staying parked at TDC longer the exhaust valve has more time to get the spent gases out actually make it even less prone to detonation than the same engine with a shorter stroke which is why they can run on less octane.
look at this way. in a regular 351w for instance, the piston goes down in it's bore and the intake valve opens and the piston starts drawing the mixture, on the way back up right before the piston reaches TDC the ignition lights off the mixture and the piston finishes compressing it and the exhaust valve opens and the piston starts back on it's way down. in the same 351w with a long rod when the piston reaches the top of the stroke it slows down a little more than the stock engine right at the top of the stroke and it stays at the top just a little bit longer and burns the mixture better and and then exhaust valve opens and can pull more of the spent mixture out before the piston starts going back down, this cools the mixture some, then the intake valve opens as the piston starts going back down the bore since it stayed at TDC a little longer this allows the cylinder to fill just a little more adding to the cooling effect started when the exhaust valve was able to pull a little more of the spent gases before the piston started back down.
now do you see why the long rod combo requires less octane, makes more power, produces less emissions and does NOT make the engine any more prone to detonation that it was before? if not, then i don't know a better way to explain it.