Slip and slide transmission

The engine swap was this winters project. If I can make it last till next winter I'll be happy. Chances are it won't be more than a couple hundred miles. As soon as I drive it a few times I tend to start the next project and put it back out of commission.

Speaking of upgrades, what's a good recipe for (an optimistic) 400 horsepower? Standard rebuild and shift kit, or upgrade to Red Eagle clutches? Any hard parts need an upgrade?