I've got a question about the differences between the 80-81 heads and the 86-87 heads. As far as I can tell the water jacket has a restritor in the 86-87 and not in the earlier. also the EGR passage is different. I had a nice pair of 80-81's that were ported and had the Manley swirl valves installed and I put them on my 86 Gn motor thinking these were the only differences. Did I goof???My GN surges whenever EGR is applied and has always had a miss that won't go away. Feedback is appreiated
Anybody???Need some help here.
Not sure about the 80-81 heads but I do know that the 78-79 have different water passages. In fact they are different enough that those do not work on a 4.1L block. Are you losing water? Did you check the head gasket match before you bolted them on?
Thanks for the reply Eric,I was getting a little discouraged. I know about the 78-79 heads you are correct. My heads matched up to the Gasket just fine and I am not losing water. I saw on the head page here on this site about the EGR passage and restrictor in the 86-87 heads. The restritor keeps the water in the heads longer keeping the head cooler. I am just fishing for Info from the GN experts,boys I wish I had kept those original GN heads.