high ports on a 150 crossflow evinrude

[keefallan]

I have obtained a 'REBUILT MOTOR ' from a company in the south. I am putting new pistons in it. In the meantime I noticed that the ports(exhaust) looked much bigger than normal. SO I opened up another 150 powerhead that I have, to compare ports with the 2 motors. The ports are much bigger. The intake ports look the same. BUt someone has definately opened up the exhaust. The ports are 1/8" higher and have the same bottom location.The sides are much closer to each other(in relation to the stock 150 spacing between ports). They are done by a machine(no squared corners). Unfortunately, I don't have any stock core plug #'s to give you. They have been replaced. I was wondering if it could be a 200/185 block? But I would think the intakes would be a little bigger. If it is indeed a 150, is there an issue with raised exhaust ports? I've ported a couple of motors(squaring up the ports) but I have never raised any ports. Anyone got some information for me? Thank you in advance.:)

[Schramer]

They should be 1.500" or lower. I know that the high hp motors were that measurement but not sure the exact measurement of a 150 but speculate it is supposed to be in the 1.550" range, maybe even more. Wider and deeper ports without thinning the bridges are a great mod that doesn't sacrifice any driveability but when you raise them it does take away from the bottom end but can be counteracted by adding compression. You may also want to think about increasing the jet sizes if the porting is radical enough. Those motors run forever if there is proper fuel (which they love), machining, mechanical parts, and a limiter on them......take away from the former or add to the latter and you may pull a Schramer :thumbsup: