Oh Yeah – I’ve been guilty of creating motors like that – see below with exhaust housing and lower gearcase from two different Evinrudes (see two shades of blue?) on my 35 Gale. It’s easy to do as long as you don’t mix powerheads with or without thermostats on exhaust housings meant for the other. On any motor I get, or go to buy, I check the model/serial label and see if it matches the welch plug data – I’ve had a couple surprises!
Dave