Duplicate post.

Lynn I know a guy in Gainesville TX and he's an older guy he did my 186s he really didn't want to open them up as they were great heads - didn't need guides but he did it and he's more or less a head specialist PM me if you would like his info

Lynn, when I purchased my first/original Z back, the guy had installed GM angle plug heads. I did the same route as you and purchased dated 186 heads with 194 valves. A lot of 202 heads have had multiple valve jobs a valve are recessed increasing cc volume and lowering compression. I just had the engine rebuilt again and thought about installing stock exhaust manifolds. I decided to stick with headers because since purchasing in late 70's it has always had headers. I request screw in studs and guide plates. Also went with comp cam solid tappet, dual pattern modern cam and roller rockers. Makes great HP and decent torque as well.