i have a crate motor and decided to go with a full roller set up since its a roller block, i bought comp cams hardware kit and a comp cam. installed the cam and when i went to put the retaining cam ring on the bolt holes didnt fit so i enlongated the holes and that was fine now. next i go and install a cloyes double roller chain and i noticed that it is rubbing against the oil passes on the block. now my friend has the same cam, same hardware kit and same timing chain but he has a zz4 block and his doesnt rub. anyone ever hear of anything like this before

 

In 1996 when GM went with the Vortec engines, they changed the dimensions on the front of the block a little.

I don't remember the details, but there are slight differences like what you mentioned.

So to answer your question, yes.

 

well after making my friends ear bleed he decided to drop his timing cover and he noticed that the cam gear was rubbing on his block also. he told me today that he grinded the face of the block about a 1/16" and it s fine now so i guess thats what i need to do. glad i am a plumber by trade