I am about to buy a 31 vanguard inboard mudboat on a haul about 14-16 ft. long. It has a clutch! I was wondering what the average speed for the boat should be and what could i do to make it go faster?

I think you are asking what kind of speed can you expect from a 31 short tail on a 14-16ft boat.

If so, I would say low to mid 20's.

Want more speed, you'll need to buy some of the aftermarket parts.

You can go as fast as your pocketbook is deep.

no its not an outboard its an inboard engine

then its a mudboat. I know my buddies mudboat with a 27 kohler only went around 18 and it was a 1438 skiff. Your prolly looking around the same with the bigger hull

PM Coodik he just finished one I believe it was that size a few days ago.

Your speed will depend on the clutches gear ratio also.

That was my motor that Coondik just finished up. My boat is a Machete (Super Godevil) type unit. The stock 31 with a new prop light boat I could get 23-25 with no wind or current, 18-20 with a hunting load. If you have the ZF transmission and it has a left hand rotation prop you are looking at 1.8:1 reduction, right hand rotation is 1.4:1. I am running a 12x14 Hopkins cleaver (LH rotation) with alot of cup and tip curl. I'll assume if you set it up like a regular mudboat you would run a regular mudboat prop since the prop won't run on the surface. The engine work I just had done was shave the heads, SS valves, timing advance, 36 intake and carb, K&N filter and dual exhaust. I'm swinging the crap out of my old prop, Hopkins is currently building a new prop to match up to the engine mods I had done. I'm not really counting on much more top end but I think my load speeds will be better. One thing I can tell you, my motor never idled and ran so smooth. That Coondik dude is the man!!!

if ur turning the old prop too much, the new prop ur getting, assuming it's either bigger in dia or more pitch/cup, should bring down the rpm's and bring up the speed.
that is unless it's too much prop, then u will have to wear it out sum to be able to turn it.

good luck, those machete's are a nice rig.

i ran mudboats all my life, most people i know still do, i would say mid 20s