Holden V8 Cylinder Head design:
The following is a basic guide to cylinder head design dealing specifically with the Holden V8 engine. The Information below is listed as a quick guide so the user can denote approximatley which series of cylinder heads they have and what is interchangeable.
There are basically 4 types of cylinder heads available for the early Holden V8 engine 1969-1989.
Early models had no E.G.R ports or emission control fitted, a quick inspection of a pre-pollution manifold either 2 barrell or 4 barrell shows that there are no E.G.R ports underneath or on top cast into the inlet manifold. The heads fitted to the engine in question also should not have any E.G.R ports cast into the heads.
Mid to late model red motors have a U shaped port cast into both manifold and heads, a quick inspection of a "pollution" type manifold shows that there are extra ports cast into it, along with having a diaphragm type E.G.R fitted to the inlet manifold.
Blue Heads have the same E.G.R type set up however, the emissions control port underneath the manifold is a hook type shape, also the later model heads are slightly ported for a bit better flow and an extra 2 bolts fitted to the inlet manifold. 3 types of inlet manifolds were available, 2 brl(on 6 cylinder models only),std 4brl and the better flowing "BROCK" manifold.
All blue V8 motors (Available from VC-VH and WB) came with 4brl manifolds.
Black heads also have the same type of E.G.R set up as the red and blue motors but the emissions control port underneath is square shape and 2 extra bolt holes fitted, also there were 2 types of inlet manifold available for the black motors, a standard 4 barrell inlet and the performance manifold known as a "BROCK" manifold.
Most black V8 heads, except some from VK automatic cars may have had the larger L34 size valves. Br careful here as there are two types of Black Holden V8 engines. The 1984 engine was 308 and automatic versions had the L34 valves only on Police vehicles or Brock/HDT cars. The later LV2 engine was 304ci and manual transmission ones got big or small valves. V5H or X7W versions of the LV2 got big valves, other small valves. All SS commodores and Brock cars got the large valves. VK SS Grp A cars had a special 'black' motor; the block was painted red.
*later model blue heads came fitted with the square port design.
** The "early BROCK" design manifold (see pic)had no dividers for the carburettor to increase flow, along with having better porting over the std 4brl inlet manifold.
The later Brock manifold has a part number ending in 5955 and a smooth plenum floor ...NOT ribbed What is Interchangeable?
basically the manifolds and heads are not interchangeable unless some modification is made to them. ie. early red heads will bolt onto the black motor but there are 2 extra bolts on the black motor manifold and 2 square ports fitted, an old trick is to block these ports/bolt holes so they can be fitted with no problems but it is just easier to have the right head/right manifold for the task at hand.ie. square port manifold to square port heads, no port manifold to no port heads etc etc.
253/308 heads are the same and are interchangeable except for the above differences.