Dave, I believe I have seen these guys at many Good Guys shows. Pretty impressive work, that seems performs really well, at least the video they have, the car does. They have been doing Tri5's with Corvette C-4 suspension all the way around for a while now. If I were going to build a Tri5 I would be sourcing C-4 suspension. Good luck deciding. Here is the link for reference, something might catch your eye about installation.
55-57 Chevy with C-4 Corvette suspension