Thinking about turbo on my/6 again...

If I was going to do this. I would use a draw thru system for an early '80s Buick Regal. GM spent millions of dollars developing the system so little old ladies can drive there Regals and not know it was turbo charged. So it is sized correctly for what you want to do.

When sourcing a unit, try to get the carburetor also. It is setup for draw thru turbos and has enough capacity to feed the system. I would use an Offy 4v manifold because it will bolt to the stock exhaust manifold and has a larger hole to mount the turbo outlet too. Make a J pipe to connect the exhaust to the turbo. The turbo inlet is 2", just the right size for the slants exhaust outlet. Then run a 2 1/2" pipe off the turbo.

This unit will put out about 9psi max and would be good for about a 180hp on a slant and would be a clean simple install in a pickup.