From Engine Masters fall issue;
P5153478 siamese bore small block capable of 4.180 bore with 4 bolt mains and thicker main web, bore, and deck. Contains 4340 forged steel crank with forged rods and pistons. Super Commando, as cast head using offset intake rockers and 2.05 and 1.60 valves. No info on flow provided. Cam specs out at 251/257 @ 050 with 6.01 lift. Comp ratio is 10.2:1. Using the M1 single plane and a 1050 Quick Fuel carb, they tested it to 520 horse at 5700 and 554 lb ft torque at 4200. They feel power was down due to the 1.75 headers they had to use and think that 1.875 would have opened the results up more.
Not outlined in the article, but taking my own stab at it, I'd say with some decent port work and a jump in compression, a 700 horse small block would be easily possible. Or drop the compression and put some artificial squeeze on it and you could realistically be at 1200+. All that at a sub 500# weight break. Only poopy thing about it is the price, but hey, you could always piece it together your self and save some bucks in the process. But, if you wanna play....
