I too searched for months. My 1995 TBI 454's would start and then quit. Took a lot of efort to ge them to continue running. Finally found new throttle bodies (rebuilt) at Guaranteed Carborators in Largo, Florida. They are great folks. Sent me new TBI's with exchange of my old ones. While they worked much better. Excessive richness eliminated, I still had the starting problem. It is now cured. The fuel pump is only activated directly for about 3 seconds on start-up. Once started the electrical power to the fuel pump comes across the oil pressure safety switch. Mine were not bad but sticking. Once cleaned out the starting issue is gone. One thing to note is that the throttle bodies contain the fuel pressure regulators. They came as part of the rebuilt TBIs. Hope this addresses some of your problems. I know it took me months to get a line on where to go. Still have not found a source for Marine Power Engine manuals.