Differences between the two are...
Vent tubes...Marine versions have them redirected into the main body.
Throttle shafts...incase of leaks, they are grooved to redirect back into the main body.
Needle/Seats...Dependant on it's use, the off-road Viton needle may be installed. Spring loaded for heavy jolts and bouncing.
Other than that there isn't much of a difference with the land version; can be rigged to look and perform like a Marine version and cheaper of coarse.
Ty Lofstrom
Texas Performance Carburetors
sales@tpcracing.com