So you talk about a stroker twice---and that you don't want the 400---do you realize that the 383 are a 350 block with a 400 stroke???? or that the 400 has a bigger 4.125 bore compared to the 350 having a 4.000 bore???
We build probably 60 sbc a year and the stock car racers love the 400s, and we sell a huge number of the Dart SHP blocks(4.125 bore 350 main size) world wide(well so far none to Africa)
We also do a lot of installing angle bolted billet main caps on the LT blocks, but pretty much use the SHP blocks for the others