question for wrechin2 on Merc 2.5 exhaust chest

[6295jimj]

I have built a few 200 hp 2.5 Mercury motors for bass boat applications and I cut the heads to 34cc and cut the front half .050 and am very pleased with the increase in performance from these two modifications. I was wondering if opening up the two long slots in the exhaust chest to maybe 5/8 would help any. I don't want to take anything away from the bottom end as the whole package is at least 2200 lbs. Any advice will be appreciated. Thks, Jim

 

[wrechin2]

Depends on year. If you are running a heavy rig the early small chest block would do better and would increase bottom and mid. That mod is to help top end breath and it takes a lot more than that to help exhaust flow it will help but you get a lot more directing the exhaust. The. Block in question have a ff stamped in it?

 

[wrechin2]

Feel free to call me.