do i have to run center-bolt heads with a tpi set-up or can i use some aftermarket aluminum heads. thanks.

 

"Center bolt" just descibes how the valve covers attach. You can get aftermarket AL heads for center bolt or perimeter valve covers. Either works fine. Select the style you want to run. What you really need to know is the angle of the center intake bolts as drilled in the head and base. Vette bases work on heads with the traditional 90 deg angle (older iron Chevy and AL L98s) while Fbody bases work with iron L98 heads from 87 or so on with the 72 deg bolt angle. Most aftermarket bases are set up for either angle.