Only way to turn up the fuel is to go a number or two up on injector size. Whats in it now 65's, 70's ?
You won't gain much turning up the boost, about all the turbo does on those motors is force feed the roots blower intake so they do not take so much power from the blower drive, more or less just makes the blower "float" inline between the blower and engine once the turbo spools up and takes over the cylinder scavenging job.
Got to understand that the roots blower is not a supercharger, it just causers a forced draft in the open intake ports and out the open exhaust valves. It blows the exaust out and pushes clean air in, but does not build any more cylinder pressure because both intake ports and exhaust valves are open at the same time.
The turbo only gains you about 30-50 hp, about what it takes to drive the scavenging blower.