Mostly it's the weight, and the engine is getting tired, the Isuzu is a 4 cyl turbocharged engine smaller and lighter also but I just can't find an adapter for the T5. At one time Isuzu made them but dealing with that company has not been fun, costs just to talk to the service Dept at Toms Truck...
I rebuilt a much lighter ISUZU 4BD2 to replace the Perkins 6-354 my wife and I installed 25 years ago, I just can't find an adapter to a Ford of Chevy T5 standard transmission, need a Standard transmission flywheel and clutch also. Can anyone help steer me in the right direction for this stuff?