Quote Originally Posted by pennyman1 View Post
That O' Reilly head is probably a remanufactured head, not a new one. The year of the truck determines whether it has manual or hydraulic lifters. Manual adjusters were used up to and including 1984 motors, 1985 and up are hydraulic lash adjusters. You can get aftermarket heads either way - just have to specify when ordering. It would help if you tell them it is a California truck to ensure the easiest install.
If you plan on modifying the engine you can ditch the factory exhaust manifold and get a set of headers, then use a non-Cali intake manifold with a Weber kit and seal up the EGR ports on the head. Once you do these mods you can delete all of the carb control related gear and the emissions junk which will all improve performance and free up the engine bay.