Double hump heads,, Pro= Cheap! flow fairly well, thick deck surface, uses all the old stuff (intakes, headers. springs, valves ,etc). Takes well to higher lift cams, room for large valves, responds to minor mods. Con= No acc. mount holes in end. Need hardened seats to use modern gas. Uses large sp plug, lacks sending unit holes needed for modern engines, Most are worn out or have been re-done so many times they are ??

Vortec Pro= new castings, for use with modern fuel, flow good for mild street engines, all acc. holes, small plugs, small c-chamber.
Con= Lightweight casting prone to cracking, needs a specific intake, Headers don't fit well, Needs guide/spring/retainer work over .480 lift. has no pushrod guide plates, requires special rockers, will not work with dome piston, Only certain mild mods work on these heads. does not respond well to larger valves.