did it on my old dawg.
http://images2.fotki.com/v21/photos/2/20477/167447/IMG_1345-vi.jpg
I cut the pipes off of the manifold then tapped them out with NPT taps and threaded regular old fittings in it. The outlet gets hot so use a braided stainless leader or something.
sucker built some pressure! I never had a press gauge on it but it filled the tank fast.