67 327 stock timing chain/cover question

[chewychevy67]

I have a 1967 327 275 hp car engine with a single chain from factory. It was original I think cause it had the nylon on the cam gear still. I am rebuilding the engine and I have a buddy who has a gm double roller in the gm box. He said I could have it for a very reasonable price but my concern is will it fit under my stock timing chain cover without rubbing of causing me grief. I don't want to change anything so if it doesn't fit I wont bother with it. anyone have info on this. Thanks, Rod.