I have a 1995 Ford LTL 9000 with a Cummins M11 currently rated at 350 HP, I am wondering if it can be turned up like the newer engines or if they were programed at the factory and the HP rating cannot be changed?

Does it have an ECM? We have a '95 N14 and it does have an ECM. But that was right near the beginning of the computer era *I think*.

Regardless, of the ECM, I'm not sure how much fuel that M11 will handle before it starts eating head gaskets. We have put 3 head gaskets on a 1998 M11 since 2007.

I'm pretty sure it has an ECM, but as you said it was at the begining of the computer era so I wasn't sure it mattered.

If it has an ECM, it may be as simple as the Cummins dealer hooking it up to his computer and changing the program. If it's mechanical, then I don't know what you do.....there's probably a way to play with the fuel pump.

I had a 94 FLD112 with a M11 in, that was rated at 335 when I bought the tractor from Ryder. Took it to a shop and had it uprated to 370 in a flash. Injector size and the turbo have a lot to do with the hp increase I was told.