I am currently in the proccess of building a 3cyl 920cc omc to run pipes.

Has anyone done this? I have had the side of the block milled and welded up to fit flanges. Obviously plugged where the exhaust used to exit so the cooling water doesnt escape down there.

What is everyones comments on expansion chambers over pure megaphones?

I will build a set of megaphones purely to run it at night and get some footage of her thrown flames out!

Everything else has been done to it. 19s fron half. Finger ported, head work etc etc. The never ending quest for more speed has brought me to exhaust work.