Found a 74 260z for sale, questions.

If hacking it up cheaply is the goal, maybe consider a small truck chassis?

A swb nissan hardbody should go close in terms of dimensions. Can be had with a ka24, which there's plenty of turbo info for. Once upon a time there used to be a hardbody race series, so handling info for that chassis should be able to be scrounged. Using a full chassis like that will give a nice solid base that you can cage and pretty much just body drape the s30 shell over the top.

Edit: I forgot hardbodies also came with vg30's, a 3.0 v6 would make a 260 fun with a bit of work.

Mad Ratel said: If you do the red line how do you account for the z being potentially wider than the miata at that point? (hard to tell dimensionally.)

Not really an issue since the only place it would be apparent is across the bottom of the door. Just buy or make a 240z filler sill to put between the front fender and the rear fender. The Miata sills will be doing all the heavy lifting.

Same situation if the 240 is narrower: don't sweat it it will just look like a flared sill kinda like what people put on as aftermarket. Bonus if you decide to go with fender flares.

going back to the 260... I find it odd that all the fanbois revere the 240.. but virtually ignore the almost identical 260.

It's the bumpers. They got bigger on the 260 and worse on the 280. Never mind it's basically the same car...

Also most everyone just calls them 240's...

http://charlotte.craigslist.org/cto/5673023000.html

better condition? :P