Th mopar guy

Well then keep your eyes on here and on eBay and CL for 340 blocks. There are some around. Expect $400 for anything worthwhile unless you get really lucky; watch out for overbored ones; others have said that going past .040" over can be an issue with limited wall thickness in some 340 blocks, so sonic testing may be in order. Watch out for excessively rusted or worn lifter bores. And 340 bores have a lot of chamfer in the tops of the lifter bores that often cause problem with hydraulic roller cams.

My son and I got a good 340 block and put in a 273 cast crank with SCAT rods and KB pistons. The piston/pin/rod weight was almost 200 grams under the stock 340 combo to keep stress off the lighter crank; re-balance was easy. (A full stroker crank set is available with forged crank if you like.) Then we put on Edelbrock heads, not ported, as OOTB had the flow we wanted. It is at 400 HP or less, not sure where you want to be. Or how original looking you want it.