We put a 18 inch set back plate on my 1982 380 comp and hung a 225 Yamaha Excell on it for the Mississippi Qutlaw circuit. The shortest race was 150 miles on a 5 mile course with the longest being 500 miles on the Mississippi River. We did have the transom cabbeled for added strength. I think the 380 will do just fine with a 300XS out back. I know it`s gonna be fast!

DB