I'm sorry to hear it Cooks, but I know from experience about the coolant puking after shutoff. You're pressurizing your coolant. You're probably trapping the air bubbles causing hot spots at speed.

As far as causes, did you eliminate the AST? Did you re-burp the cooling system properly after the relocation? How about extended-life (pink) coolant? Also, Dave @ KDR told me at the time of my o-ring failure that he thought watter wetter contributes to it. I also think just heat over time degrades them, and the car should have come w/ the upgrade teflon/silicon seals.

Recomendations:
A reman is a reman, so you can get it from anyplace that has a good price. If you want to keep your car, i'd recomend having the reman rebuilt, and at least having upgraded water seals put in.

Dave @ KDR did a fantastic balanced/blueprinted motor with ported oil/water chambers, upgraded orings, and a mild streetport (still idles smoothly) and stock apex seals for me.

Along the way he checked out virtuially every ancilary system on the car, and gave me full report. It was worth the extra $$ to me.

 

I'm with Pete...did the same plus intake, exhaust ports, eccentric shaft mod, ported water passages, etc. See sig for mods.