Figure out your available dimensions and then give an expert a call. I highly recommend Bell Intercoolers; I worked with Gerhard when I designed my intercooler. Very sharp and helpful guy to talk to... and they build nice stuff too.
Here's what you're looking at to support 1000hp or so with minimal pressure drop:
https://lateral-g.net/forums/showthread.php4?t=8304
https://lateral-g.net/forums/showthread.php4?t=9204
The intercooler will be plenty adequate for the new TT LS2 I'm currently building. It's about 4" taller in core height than Gerhard's recommended "minimum height" but I had the room to go up a bit and he suggested if I had the room to stretch it a bit to add additional efficiency. The core is 27" x 12" x 3".
If you can't fit an adequately sized intercooler you can actually hurt power because it becomes a restriction. You want the largest cross sectional area possible in the charge air direction for minimum pressure drop.