If your thinking mopar BB a well built 383 would be most weight/budget friendly bang for the buck, 400's can be built to a nice stroker with a 440 crank making 452 cubes but I have heard of crank problems w/ high RPM's due to alot of 440 crank being turned off to fit the 400 journals. A 440 can be stroked to over 500 inches with a 4.15 crank, $$$$$$. Another note , a Chryco 360 can also be stroked to over 400 some odd inches, making a relatively light and stout mill. I have some 383/440 stuff but you should be able to turn one up relatively easy.
1976 Cherokee NT 232 cid,HEI, 2brl, MSD6A, SM465/NP205, SOA/Shackle Flip, 35x12.50 Mud Chain Saws, Dana 44's w/ 3.54.
1976 J10 258, 1brl, T-15, Dana20, Dana 44's w/4.09's, 32x11.50 BFGrizzle All Tizzles. Optima Battery
1997 Dodge 1500 Sport Cab Laramie SLT, 360, 4WD, 3.54 Posi, RS9000's, Optima Battery and MSD 8.5 wires. Borla Cat back system.