Correct me if i am wrong please. But an 87 Iroc has a hydraulic roller camshaft, not a flat tappet correct???

 

You are correct....

 

So i guess the need for a motor oil with a high zinc content isnt really a concern with these engines like it is for flat tappets? ive been running castrol gtx 10w40. what do u think, good or switch to something else??

 

If your car is stock, check what the manual says and go with that. I've been using Amsoil 5w30 with no problems.

I'd offer to check my manual for you since we have the same car, but it's 75 miles away right now >.>

 

Thanks for offering to check the manual for me. the dipstick says " use 5w30 energy conserving".