if you got a older zf5 with a 351W/302 bellhousing it will physically bolt up to a 300 I6, they carry the same bolt pattern... now as to what clutch and flywheel you would need i'm not sure
if i was attempting the swap i would probably use the throughout bearing from the V8/ZF (it will be internal and hydrolic) , you will have to use a 300 flywheel because isn't balanced like the 351 or 302.. IF it (flywheel & clutch pack) is the same thickness as the V8 flywheels then it would be a piece of cake
when i swapped my half ton from a 300 to a 351 i used the 300 bellhousing 351 flywheel and clutch and 300 throughout bearing so that it matched my tranny snout and was the right thickness
sounds like a cool swap... i think it wouln't be that hard
