Andy's right. Traction and intended use will dictate what might be needed to be done with the drive train.

I had a 727 and 8 3/4 behind a 499" for years. Did a lot of KOS with it, too. Most of it done with drag radials. They held up good.

So, with good parts and good builders, a 727 and 8 3/4 would probably hold up well for you.

As to what cam, heads, and intake to pair with the cubes, tell us what power level you want, what you want to do with it, and how much drive-ability you are willing to sacrifice to get it.