4.3L Chevy v6 questions

Anyone know if late model 4.3L Chevy V6 ('99+) heads, manifold, csfi, and
distributor can be fitted to an early gen 4.3L (85-91) short block without
any significant snags? Basically looking to use the short block from a
known low mileage '91 engine, to fix a '99 vehicle that spun a rod-bearing
and would need machine work the owner cannot afford. The wiring, computer,
etc. will stay with the '99 vehicle. I know that we'll need those Pioneer
conversion rocker studs to adapt to adjustable rockers because t\of the
later model "zero-lash" setup, but not sure if there will be issues with the
distributor drive or other?