i bought an 18 ft checkmate bowrider this summer becuase our cig was not running all summer but have now grown to like the boat very much. we are planning on keeping it awhile and are redoing the interior at this moment. it is a 1984 with a 1984 evinrude 235 crossflow. i am interested in rebuilding the engine this winter as well as performance upgrades( portting, intake, crank, larger pistons, heads, carbs, reeds, etc.) does anyone know of a reputable machine shop that specializes in this type of work for outboards? also, if it is being mass produced does anyone know of anyone that builds a blower/supercharger that could fit this engine?

Might have better luck with an answer on www.screamandfly.com

stinger,
I had a 235 back in 1980 or so.. I had it ported and all it did was cause problems. I never did feel that much of a power increase, but the locating pins on the pintons would get pounded into the pistons and the rings would rotate and catch on a port. I went to OMC and they told me that they had seen the pins get pushed right up through the top of the piston.
In my opinion, it is much easier to bolt on a 250hp stock motor and stay boating. I had the power head apart seveal times for different things. The guy that was doing it was good, but the motor didnt like being modified. I hope you have better luck, but I swore off modified outboards after that. Now it is all BBC..
Hope that helps
Dick