I want to buy a 83 Nissan 280zx and drop a Chevy 383 in it. But all I found were V8 conversions on Datsun 240z's. So I was wondering if the 280zx and 240z are alike inside the engine compartment?

The size of the engine bay is similar and there are lots of people putting V8s in 280ZX cars as well as Z's.

See www.hybridz.org lots of talk regarding V-8 Z & ZX's.

Also, I know one nice 280ZX V-8 is owned by Ross Corrigan of Canada. He has a web site with tech articles and pictures at http://home.istar.ca/~zxv/index.shtml and I believe he can be reached by email at 280zx@home.com. I don't know him personally but he is a frequent contributor to the internet Z-club mail list and has a Z-ZX parts distributing business. I am sure he would be happy to get you started in the V-8 direction.

Have fun!