Totally interested in your project here. I have a Tahiti with a sbc and have been wanting to do the same thing as you. The Schoenfeld dry headers have my eye but i have never been too sure about how to route the water pipes to properly do this.  Good luck I hope this goes good for you.

Sent from my SM-G900V using SoCal Jet Boats mobile app

I'm thinking it's a 1970 tahiti. At least it looks exactly like mine. Let me guess sbc and a berk. Looks fun.