double roller clearance problems

has any one installed a double roller timing chain into a 87 up hyd roller block? what brand did you install?
I was intending to install a edelbrock timing chain and ended up pulling it back off and installing a factory chain because of clearance issues. I ginded the block above the oil galley that fixed most of the problem, but after bolting the cam gear down I find the cam gear dose not have proper clearance between the gear and thrust plate and will not turn. maybe I have a defective unit?...

I used one from Comp on my blazer, and it cleared fine

Factory roller cam timing chains are totally different than aftermarket flat tappet or aftermeket roller cam timing chains. The offset on the cam gear is totally different. If you're using a factory-style roller cam with the retainer plate and all, you want to use the GMPP performance-replacement single roller chain set. They're cheap, they fit and they're dead-nuts reliable.