Thinking about turbo on my/6 again...

Spool time is controlled but the size of the exhaust housing of the turbo plus the amount of exhaust volume being pushed to it as well. On mine I have .96 ar housings on my twin 76mm and on a 428cid small block my boost comes in around 4k, but I have 4 cyl compared to your 6 pumping into it. Size wise depends on how much power, just a helper can run a 45-50mm turbo with a small .68ar or around there for sooner spool time. Intercooler depends on if you want a cooler a or charge even at 5-8 psi is still helpful, can run air to air for more of a daily driver. There are mods out there for a blow through that can be done at home with the right tools or some of the fittech can handle boost if that's in the cards.