Beginner question here. Note that I own some machine tools but still
haven't had a chance to start using them! So don't assume I have any
commonly understood machinist knowledge cause I ain't one. Yet.

I've got an old, very well used, BP that I was going to rebuild but had a
chance to score a lightly used BP J-head Series 1 so now I've got two. The
one I just bought is set up for MT3 tooling. Can I use this as is or should
I change out whatever parts in the spindle to make it use R-8 tooling.?
What parts might be involved? The old BP is pretty worn so I don't want to
swap heads or take parts out for the new one.

Thanks.
Steve.