340,to stroke or not to stroke
Well, I dont see a dollar figure, or much about the rest of the drvietrain. So with your experience, I'll assume you know what a powerful street engine needs, and providing that is no problem. As for a solid engine for a street and occasional race, I'd go like this:
Either 340 or 360 block, sonic tested, trying to limit oversize to .030. More than that in terms of bore is more $$ for pistons, assuming the block can accept it with minimum of .150" think main thrust thickness. For a rotating package. The cast cranks are very strong. They will run at 500+hp for a very, very long time. Pair them with a decent set of H beams and good pistons. I like the Eagles and Diamond pistons. With a hydraulic flat tappet andd performance machine work you should be spending around $3500 for the short block. For heads, a set of RPM 63cc heads, the RPM Magnum heads, or a set of the new casting iron Magnum type performance heads. In any case, you're looking at somewhere around $1500 for heads. I have one of the Crosswind type air gap intakes that have both patterns. It's $100+ cheaper, and will fit any option, and looks pretty good to me especially for the price. The complete engine with someone assembling it for you will run around $6300 using nothing but new parts. Depending on parts choices, I would expect an engine built like this to make peak torque under 4000 rpm, and peak power in the 450-500hp level between 5500-6000. More than enough for a serious street car, and able to run on any fuel at gas station you drive past. Also, if you can find a good running 5.9L Magnum core, you will need an electric fuel pump, but that can be made into a really nice 408 with Magnum heads and a hydraulic roller cam with the same power numers.