Ok gentlemen. I just got my 4 cyl block back from Chris. I am replacing the p-head on my boat. Its the motor I have been talking about that has a broken ring(and a bad head too, I'm sure). I got 6-7 years out of it(there's a longer story here), and it has had a bad hole for 3 years now. Its still running right now. But the block is junk. Its got an overbore of .064 in one hole, and its got compression around 160 in that hole.....crazy. The other healthy pistons are 145. The bad hole..........90. When I build this other powerhead, I was wanting to maybe open up the exhaust in the tuner (megaphone) area. I know the v4 is much smaller than the v6 in that area. I dont want to do any race mods or anything like that. But is there some way to free up some power down there? I am not asking for race secrets, just pointed in a direction to free up some air to moveit better thru the bottom half of the motor. I am trying to bring it closer to a real 140 crossflow(prop rated.....even tho it never existed). I am using 135 heads.

I know the 77 megaphone is a unicorn...........but is there other things to do without getting radical. I am just looking to free up a few more hp......

I am sure it will force me to rejet, but I dont care about that. I am looking for free power(jets not withstanding).