Nice work! Do you have a link for Flatout Gaskets? I'd like to check those out.
I can't add much detail but I had a 300 turbo running on propane in my 67 Mustang about 48 years ago when I was 17-18 years old and my memory of the details has faded. I ran the turbo with two different heads. The first was an prototype single overhead cam hemi from Ford. See link below. Then I had a large valve ported 240 head. I ran around 7 or 8 pounds of boost max with the hemi head as my dad did not want me wrecking it. I ran about 10-12 pounds on the 240 head on the street. Used both water and then alcohol injection with the propane. It had a large air research turbo. No intercooler. Custom exhaust manifold with wastegate. Aluminum intake, probably Clifford. We took it to the drag strip once with the 240 head and jacked the boost up to around 15 to 18 pounds, can't remember exactly but with small tires it was useless trying to make a decent pass. My dad was worried about the bottom end so he didn't want to go any higher on the boost.
Before I got it, he ran the engine with the 240 head naturally aspirated at Bonneville with weber carbs and then at the Pikes Peak hill climb with Hiborn fuel injection. The next year he ran a turbo on it at Pikes Peak. So when I got his Mustang we put this engine in it. It had a copper head gasket with a ringed deck, head studs. I can't remember if the crank was forged or cast, most likely forged. Custom forged flat top pistons, can't remember who made them. Stock distributor. 4 speed Top Loader with a overdrive unit on the rear end. Ed Iskendarian used to make custom cams for my dad but I don't what the specs were when I had it in my car. I know it didn't have much overlap because I used to complain to him about not having any lope and being a kid in high school I wanted a mean sounding idle instead of a tractor motor. However it was the fastest car in school.
Hemi Head 300 6