parts exchange on 3.9 engine rod bearings

Ihave beeen working on my son's 93 range rover classic . He had run it hot back last Oct on the way back from Land Between thA Lakes on I-65 here in Alabama. we towed it back in (on a rollback) . a waterpump belt had gotten loose and jumped off the tension ideler pulley ( boy what a little thing caused a big problem. Blown head gasket. we reworked the heads and had them milled put it all back together and cranked it back up . motor had knocking sound .Later I pulled the pan started ckecking the rod bearings from front to back, as i went further back the bearings looked worse, but crank looks great !! I priced new rod bearings and as you know they are 3 to 4 times the price of normal parts. so while waiting on the extra money i got to thinking about the legend of this motor . i always heard it was copied or purchased from gm so i've been told. who knows? but i went to auto zone and asked for buick rod bearings (1963 skylark v8 215c.i.) and compared them and were very very close so i purchased 2 and installed them but had finished wanted to here from someone who may have a little input on the subject

You are correct, Land Rover bought the cast rights from GM and from that the 3.9L was born, the stories you heard are not just a rumor, they are true