[Scarebird]

One thing that is superior with the GM Gen IV and V's is that they have simple mechanical chain tensioners. They mount ot the block behind the chain and have a spring steel lined with Teflon? UHMW? guides.



This would be an excellent solution instead of undersized sprockets. But the issue is that chains come in various widths and thickness for Pontiac V8's
Another solution may be like this:



Instead of holes it would have slots and the chain guide flats would be rounded slightly to allow different engagement points. A pair fi;e-like grip plates would sandwich the guide and not allow movement. You would of course use a template to drill and tap the block for the attaching bolts.