here's a thought, 340 block, 360 crank turned down, 360 pistons .060 over, 372 cubic inches on the cheap. There's your 400 rwhp with the right cam and heads. Best of both, minus the forged crank. Assembly would have to be internally balanced like 340.
Thats mine. 60 over 340. 3.58 crank=378 inch. BTW my enging guy says cast is softer and better for the twist. til you get up into the hi dollar forged cranks.
Been thinking bout selling mine. Over 125 guys looked at my post in parts for sale. No thoughts on its value..