Brian,
The part numbers are the same for the 501 cylinder from '94 to '98. I am pretty sure that the '99's are also the same and can't say that the 2000 will work or not. And the cylinder heads for the 501 and 600 engines up to at least '98 are interchangeable, and again I believe that the '99's are the same too.
there used to be a manual available in the Download section. Maybe i am just missing it, but if you can't find one send me a PM if you'd like a hardcopy of the '98 manual mailed to you.
Dez