Sounds like a decent deal you got if its in great shape. Personally I'd slap a V8 in there because thats what I am doing haha. Members on here have made some good numbers on here with L28 converted to fuel injection, mega squirt, and running a turbo. And there are people who have V8's who are making good power too. It's all your preference . If it has 49,000 original miles, I'd sell it haha, are you sure its not 149,xxx miles?
I wish my 240z had new carpets and an uncracked console =/. Its close though lol.
-Josh