I am looking at buying a 97 F-150 with a 4.2 that needs the shortblock rebuilt.I know where there is a 94 3.8 that I can buy for cheap and use temporarily.Is there any reason I can't take the upper part of the 4.2(heads/intake etc.) and bolt them on to the 94 shortblock?I understand there is a balance difference between the 94 3.8 and 97 4.2 so I would either have to get the 4.2 flywheel rebalanced or get a 3.8 flywheel for that year tapped to accept the larger F-150 clutch provided it is the same overall diameter.Is this correct?