Absolutely do not go the frame cutting route !!!!!!!!!!!!!!!!!!!!!
The swap is a quite simple job much as hot rodders have been doing since the
first engine swap. Simply assemble the engine and transmission and set it
into place with a chain hoist, boom or whatever. Then where the motor mounts
should be, simply fill in the space with mounts made right there. Or order a
set of mounts from J.C. Whitney or most local speed shops. These mounts are
made to mount a chevy engine into any fame built like the M725's. You may be
able to use the stock chevy exhaust manufolds or you may have to use a set
of exhaust headers. Either way you will have to have an exhaust system
built, which any local muffler/exhaust shop should be easily able to do. You
can either use a transfer case that bolts right to the transmission or use a
seperate transfer case as was origionaly used in the M725. These transfer
cases are readily available from dealers in surplus parts at very reasonble
cost. either way you go, you will have to have new driveshafts made up.
three shafts are needed if you go with a seperate transfer but only two are
needed if the transfer is bolted directly to the transmission. I know of one
fellow with a M725 who drove his complete vehicle into the shop one day and
drove it out 3 days later with a 350 Chevy and the Chevy transmission installed.