The same outdrive they run on the big blocks with up to 500hp just gear them differently my boat has a 350 with 250hp drive runs flawlessly as far as the manifolds and risers they are all clean and I just had them off a month ago when I serviced boat and changed thermostat pulled risers to inspect and they are clean and like new you are welcome to call me about the boat if you like 772-284-5723 thanks Tin
