On the OE small block Chevys, it seems if you want to run a double roller timing chain the plastic cover won't fit.
This is my first OE roller block and I'm puzzled, do you just use a steel one? And do these use a torrington bearing?
Thanks.
I did a search but nothing that I could find.

Try here . http://www.summitracing.com/parts/sum-g6300 I used this one on my 383ci w/double roller .

deep,
This is a short water pump set up, no bypass. So that cover won't fit. And it looks like the factory plastic would need trimmed also. Looks like research on a steel one will have to work.
Thanks

Depending on who's gear you are using, double check the clearance between the back of the gear and the raised casting by the three plugs around the cam tunnel. A little grinding may be needed.