I don't think the cummins 4 will push it and they are getting expensive. That's the route I am going in my 53 one ton.
If you have 39 inches in the engine bay you can use a cummins 5.9 out of a dodge truck with an SAE 3 adapter.
Cheapest way is gonna be a 6.2 or 6.5 GM diesel.
keeping the NP540 won't be a problem with any diesel.
Perkins might be a cheap way to do it, but the flywheel and clutch won't be cheap.
Again, I refer someone to Brian at
adelmans . No affiliation, just a satisfied customer. He can probably hook you up with a complete 4-53T at a decent price.
