I'm going to be building a 4.1 (291) motor soon and I'm looking for some guidence on what heads to port. Should I port a set of GN 8445 heads or the stock 4.1 heads. Is there any difference between them and is there any info on how to port them in one of the Forums.
If you do not have use of a flow bench, stick to matching gaskets and cleaning up under the valves ( guide bosses, short side radius and just blend the bowl area) You could make them flow worse if you have never done it befor.
If you do not have use of a flow bench, stick to matching gaskets and cleaning up under the valves ( guide bosses, short side radius and just blend the bowl area) You could make them flow worse if you have never done it befor.
