MP does make a carb intake, Bob is getting the kit that uses a takeout and with a wiring harness, manifold, and some other stuff to put it in a non computor controlled car. I don't know if the manifold is available seperately. Start at the beginning of the thread for Bob's post on the kit.

Do you have to run the coil packs on these or would a crank trigger MSD type setup work?

no idea on the msd

Is the 5.7 buildable to a 6.1 or more? Are there stroker kits available?

I THINK there are a lot of differences between the 5.7 and 6.1, no stroker kits yet but there are cam kits.

but I am unsure as to how readily avail. parts to rebuild these motors are.

stock parts shouldn't be a problem, not much aftermarket yet.

-Daty