Thanks jonesy. When the engines go back on the dyno they will have full accessories. These runs were just to give me a direction for parts selection. They are going back on for final tuning. Then we will see how much of a difference accessories and marine headers make.

All my 4150 intake testing was done with a plain open spacer based on my previous dyno experience with this combo. All the 4500 intake spacers were the HVH type based on the builders experience. I would like to try something like I quoted in post # 18 when they go back on, but funds and/ or Steve telling me to get this over with will likely prevent that from happening.

Thanks for all the runs and info. Very interesting.