Just yesterday I pulled the head off my 4.0, and noticed how TINY the exhaust ports are. Wonder if it could benefit from some port work. I also found a replacement head, thicker (iron) casting and better flow (They did not provide numbers), no core charge (Due to brand new casting), for only $499, valves and springs installed..... not worth it to fix the old head if there's anything wrong with it. It's in the machine shop now for pressure testing..... I hope to build this engine up in the future, stroker kit etc... but for now it will go back together the way it was, bone stock. I might do some port cleaning and blending while its out. Seems to be hard to find anyone who REALLY knows these heads on online forums.
