There are a couple of radiator manufacturers that specialize in custom radiators for racing and other applications. You can specify the core dimensions, number of rows, number of passes, mounts, and end tank style/hose fitting location.

A full custom one might not be cheap, but if I had to guess I would think that they likely already make one close to what you would need that would drop in.

I have a Fluidyne in the track/autox car, and am very happy with the quality, fit, etc. This is on a twin-turbo RX-7 which is pretty tight up front with intercooler and AC stuff in that location too. I think the shop I use found a Fluidyne core that was pretty close to drop-in with some minor mount fabbing and now offers this as a retail item.

This page from the Fluidyne web site has one that seems close to what you are looking for Gregor, although I do not know how the hoses are arranged on the 292:

http://www.fluidyne.com/pl_racing_universal.html

I am guessing one to fit the Chevy ought to be way cheaper than the one for the rotary...