Toyota Repair: t-100 engine, engine rebuilder, camry v6

Question
Hi,
bought a 1993 t-100.  Tried the engine, it started and sounded well.  The guy bought it for 3500 and drove it for a while until "he thinks" it overheated and blew the head gasket.  He agreed to sell it for 500, body etc in excellent shape.  Towed car to garage and now it knocks.  Looks like I need an engine for it.  My brother is familiar with other toyotas and he says i can buy a camry v6 and put it in.  Sounds weird to me.  Any ideas?  Can I rebuilt it?  Are such engines, used available?  Cheap? Expensive? worth the expense of take it to junkyard?

Thanks

Answer
The camry engine is completely different and is not a viable option, it may be rebuildable, if you do most of the work except for machine work yourself, it may be worth the trouble, used 3VZN v-6 engines are hard to find, another option may be to just locate an engine rebuilder that has a remanufactured long block and go that way, in either case it's probably going to cost about $2,000 even if you do most of the work yourself.