How long ago was it that 1 H.P./1 cu. in. was a holy grail, in this case 355 H.P.? Maybe you can take a look a few dyno tests here:

http://www.ryanscarpage.50megs.com/combos1.html

It would seem that NASCAR engines run in the 700-800 H.P. range in the 358 cu. in. limit but they have to turn high rpm to get there, remember that

H.P. = Torque (ft. lbs.) x (rpm/5252)

so if the engine can turn 6500 rpm or more, high H.P. is attainable, BUT then you have to sweat out a LOT of details to keep the engine together at high rpm for a long time. Note many drag racers replace a lot of engine bearings between runs but NASCAR engines have to stay together for about 500 miles at high speed. It also would seem it is easy to get 350 H.P. from a SBC 350, but if you look at the dyno curves the higher the peak H.P. the more the low rpm torque suffers and high rpm engines then need high stall speed torque converters to get up into the good torque range. Then again Nitrous looks enticing or even a positive pressure supercharger, but then you better have good rods and a strong bottom end, so there are a lot of tradeoffs. It does seem that many NASCAR engines can achieve 800 H.P. at high rpm but there are many expensive parts and a lot of trade secrets involved to get there. After you look at the Ryans Dyno list maybe you could work toward 400 H.P. realistically, but even then with normal aspiration, the low rpm torque may fall off and you will have to run a big (long duration) cam which will reduce the low rpm torque. If you have a lot of 350 blocks why not try to do the slight grinding and buy a 383 stroker kit. If you mess up one block by grinding the clearances yourself you can just call that a learning experience and do a better job on a second block, however in my experience this kind of "learning" is also expensive. Well anyway have fun and build something after you study the Ryan's Dyno Set.

Don Shillady
Retired Scientist/teen rodder