Torsion bar/K frame question

This is still a little way off but I'm trying to get an idea of the parts I'll need for my project. It is a 68 Barracuda that had a slant six/auto trans. I plan to swap a 360 in using Schumacher engine swap mounts. They strongly advise upgrading the brakes to discs and I get that. They also advise upgrading the torsion bars. Are the ones sold for 68 A bodies through Mancini/Summit/etc. the right size? Will there be any problems attaching the larger ones to the slant six K frame? And, while the engine is out, should other upgrades be made to the front suspension and can they be done in a garage? I have little idea what I am doing, got tired of the car sitting year after year, and decided to just do it guided by you all. Thank you all in advance for the help you've given me.