Re: 427 BBC clutch pad choice
I would definitely go with an aftermarket clutch & pressure plate.
Here are a few items to consider.
The Centerforce works pretty well for moderate applications & most will be happy with it.
Under 500hp, you should be fine.
For high rpm, over 6500, you may want to stay away from a diaphragm clutch. Many do not want to shift well at high rpm. Not sure where you are shifting at.
I had a lot of problems with other clutches & stepped up to the Street Twin myself.
I had both a Hays & also a Centerforce & cooked both of them. I could feel them slip on the gear changes, but this was with approx 600hp.
The McLeod Street Twin is a serious clutch.
I went with the B&B/Long style pressure plate to help the high rpm shifting (I shift at 7200rpm), but pedal pressure is very high. I can say it will not slip, but it also grabs pretty agressively just pulling out normally, making you change your driving style. Probably not something you want to drive everyday in traffic.