I remember the kit for that conversion I believe it was called a Scarab. It came with the adpaptors and the body kit. I was thinking of doing it to my '79 280. But I would think today it would make more sense to put in a V6 out of a 300ZX. The Scarab kit was popular because of the lack of a V6 or a V8 that was available.
I found a link to a site with a big block Z, but unfortunately the link is dead.
You can make so much power with a small block it just seems ridiculous to put in a big block.
I made 411 RWHP with a streetable cam in my 94 Camaro, so throwing an LT1 like that in a low-mid 2000 pound car would be damn plenty for me (as a road racer). For more power go for the better LS1, or blow/turbo it, why the extra 200 pounds of the big block though, yeck.
as far as doing something like a fuel injected LS-1 or LT-1, save the money go carburated. It is definately easier (a lot less wiring for fuel management) and with the price difference you probably could get a supercharger too.
I thought about the Scarab setup, because Hooker has long tubes ready to go for the car, however you can't use a T5 or a T56 with that setup
With the JTR setup (Jags That Run), you have to run custom headers, or block huggers, but the manual trannies work fine.
While I thought about carbed setups, having to buy new heads/intake/carb to get something with decent power output, I figure the price will about end up in LT1 territory, I plan to spend no more than 2k for my LT1/T56 setup, already have Tunercat etc ready to go.
I own a 240Z with a samll block chevy 350 V8. i love it. i loved it some much i cracked the under body because of all the power and torque. i went the carb swap. it was a lot more easier and cheaper. I got a manual on how to do it from jtr.com. it is a lot of fun just make sure you do some reinforcing to the undercarage.