Update- Compression test done- Fair results for a 150,000 mile motor. Heads off- need to rebuild, guides loose- excess clearance. Minor damage to piston top from small butterfly pieces.What is amazing is no valve damage! And no butterfly parts in/on piston. Must have gone out the exhaust! Plan for now is to rebuild heads and make it a driver, then begin finding 3.8 conversion pieces. Are there any 3.8's to avoid? I have found several for very reasonable prices(compared to 3.5 dohc), and also wonder about DOHC chamber volume differences- maybe I should post questions directly to Charlie's post about the 3.8 conversion. So far I haven't noticed a resolution to the domed piston issue. Now Charlies' is on the road,I'll keep waiting for an update from him on detonation/driveability. When mine is a driver,I'll sort out other bugs. Found Gaskets at Autohaus. Thanks for all the input so far! All help is greatly appreciated.

A short note on my detonation issue, when I was assembling mine I had the wrong timing blade, Part # was correct but Mitsu sent the wrong one to my dealer. I indexed one but did have the timing advanced to much. Yesterday I installed the proper one that my dealer got for me. I am going through some other maintenance and cleanups while the truck is in the shop.
I will drive it tomorrow so an update after that.