For twin turbos, I don't think you want 8 into 1.

This is supercharger talk, but you'll run into some of the same issues. Other discussions there also:

Supercharger build - 460 Ford Forum

Your topic is turbocharging, not Ranchero, so you may want to post in this forum:

https://www.ford-trucks.com/forums/5...r-vehicle.html