I would waitunti there was a better cam to throw in there. That cam is going to give you minimal gains for the 3-6 hours it's going to take you.

If you haven't worked on one of these before it's prolly going to take you more than that, prolly more like 6-8, over a weekend.

About the chain though ... I would wait a little longer, and swap the chain when you got a bigger cam in there.