The 310 HP, looks like 3ZJ21620, would be my guess.

I see the old engine was 24.0 degree BTDC timing; but my guess is the 310 HP engine is probably 18.0 degree BTDC . Fuel injection pump won't swap, that for sure = probably different compression ratio and pistons and nozzles, etc.

Did the guys, that removed old 310 HP engine cover or tape the intake ports? (= real easy for parts, washers, nuts to fall inside the engine, if people aren't careful about this stuff {remember, those guys probably didn't care about "that" engine, during removal, so they might have been somewhat careless, about any debris falling into cylinder head intake ports})

How many miles, on old 310 HP engine?

 Time for engine bearing replacement ?

I would be worried about your old 360 HP turbo, because you had "metal in the oil" during that failure. (= metal debris might have gotten into turbo's bearings)

I'm just guessing, but I assume the easiest, cheapest option, would be to swap over JWAC components to 310 engine, buy reman turbo cartridge(center part of turbo) for a 360 HP engine, and install on that the 310 engine (may have to double check if exhaust manifold would be also be required during swap (whether a different part number or not); then finally just have someone turn the fuel screws, on the 310 HP engine's governor up to around 360 HP's fuel delivery amount. {this method, isn't "by the book", but you didn't want to throw a bunch of money into this unit, either}