340 vs 360?

The 340 has been sitting in my shop for a while, I listened to it running before it was pulled sounded real healthy has a mild cam, internally stock as far as i know, Motor was freshened up awhile back heads look real clean dont think they have been ported, Guy pulled #s matching drive train to replace with Hemi go figure. Headers are for an A body. Dart is now a 4 speed setup 8 3/4 4.10's with sure lock.
The 360 is in a 84 Ramcharger 4x4, motor was proffesinaly built by Nixon trucking 2000 miles ago this guy spent all kinds off money having this thing built all parts are new not sure on the cam specs claims it was dynoed at 415 rear wheel horse, The truck runs perfectley he drove it to work for a few months and got bored with it now i have the opurtunity to buy it for a couple grand recipts alone for motor are at $8000 some guys have too much money.