Time for a swap

[TheRipper]

The KA24DE in my 93' 240sx recently went to hell I found out from a mechanic. The bolt that holds one of the cam gears stripped out the thread inside of the block so basicly the cam gear was chillin on a bolt in a hole in the head, not screwed like it should be keep in mind. He says they cant re thread the head because a bolt bigger than that wouldn't fit through the cam gear itself. I don't know what kind of motor to put in this thing. I heard you can bolt a KA24E head to a KA24DE block and it wont do too bad, why is this?Is an SR-20 practical? It'd be out of an s13 because of money issuses.I've found RB20's and CA18's. I'm looking at like $2,500. Possible? or not?