To do it with a 4.250" base bore engine, +.060", and a 4.250" stroke crank it will be tough. 850 HP is a more reasonable expectation if limited to 24 degree head or limited intake and carb size. Lots of RPM and a head with 2.350" titanium intake valves. .850" lift cam. (Call Kirk at Bullet for that.) May need .904" lifters. Shaft rockers, Triple PSI spring, 7/16" pushrods. Molnar steel rods and crank or GRP aluminum rods. Vacuum pump. (A top notch engine builder would get north of $30K and might not get you there.)