Frankenclutch?

[Jimal]

So it turns out that the 350 that came in my '65 K10 project is actually a 400. No problem except that the P.O. didn't realize it was a 400 and used his old 327 flywheel. That means I'm now pulling the transmission. I was originally going to go the cheap route and use one of those adapter weights, but discretion being the better part of valor I've decided to bite the bullet and replace the flywheel and clutch.

My question for the experts is about the interchangeability of these parts. Will the stock clutch for my '65 bolt up to a newer flywheel (I picked a '75 400 for the application, since most of the upgraded parts came from a '75 pickup). Pardon my ignorance on some of these things. I'm a bit rusty on my Chevrolet knowledge and I've never owned a Chevy pickup before; certainly not one of this vintage.