My 73 340 stock block (has a 3.79 billet crank)made 662 hp at 7300 rpm on 93 octane. It has no hard block or any kind of filler in it. I have not turned it to 7300 yet I shift at 6800 rpm and have run a best of 6.21 @110 in the 1/8 so far at 2950 lbs. So far it has run fine for a couple hundred passes and a lot of street miles.
