The Jacobs (R-755 or L4MB) is available in several ratings - 245, 275, or 300 hp IIRC. Some are more favored for reliability and cost of operation. I think the 300 hp engine has higher-compression pistons.
There were also some pre-war civilian models, L5MB (830 cu. in.) and L6MB (915 cu. in.) The latter was 330 hp I believe.
From a maintenance viewpoint, the best thing about the 190/195 series is the swing-away engine mount. Servicing the accessory package would be VERY difficult without this feature.