Tex, I've had 2 153s and now have a 181 ci version of the Mercruiser 4-bangers. They are basically 2/3s of a Chevy six. The only problem I see with the Mercruiser engines is, the cams are designed for wide-open use and they don't have much low-end torque. The first one I had really ran well at fast highway speeds, but was awful doggy around town. I had a cam ground and it really made that sucker scoot! I imagine the same thing would hold true for your engine. Wolverine makes a good RV cam, or call Tom Langdon (which is a better idea) and see what he has on hand. You can e-mail Tom, or call him. See the ad on the back page of the 12 PORT NEWS.
