Just thought I'd mention that those heads have angled spark plugs, and may prove to be difficult to get a set of headers that will fit. Might be why they are a good deal? See post #3 in link.
I have a set of the straight plug 70cc pn6073 and that was one reason for buying them.
Not saying you can't get headders for them. Just that its something to make sure you look into before buying them.
angle plug or straight plug heads ?which is better [Archive] - Chevelle Tech