I have a flat bottom boat and I think I have a 5hp motor, and I say think because I can't find a model on it any where because it's a little rough. But the serial number starts GCACK and the internet says its a gx160. Anyway, I am relatively new to mud motors I was wondering if it is gonna be big enough for a long tail?

You can run a small LT on it, 6-9 hp or so, with no problem assuming you are on the smaller side. How wide is the bottom?

3' maybe, that's just a guess with out measuring it. I just wanna make sure a 5hp is gonna be big enough for gear, 2 guys, and a dog.

Depends on total weight of everything going into the boat. It sounds like you may be asking a bit much of that boat, unless you and your friend are little guys. Boats that size tend to be a bit tippy.

you wont be movin but at a snails pace and wouldnt want to go out on the water with too much of a breeze.

Had a 9hp lt on a 1430 bateau. It moved with three ~175# guys and gear. Less than 10mph I'd guess
But it did move and beat the shit outta the 9hp outboard we had before which was always shearing pins on the prop. Rode pretty low, but we hunted flooded bean fields, so it didn't really matter.

Why not get a little copperhead surface drive, their little motors seem to work well.

There's a review by a guy with a 14xx duracraft w a 12hp ch on here somewhere.

Well, I acquired this motor for free along with the boat. Thats kinda why I'm sticking with it, also the warden a.k.a my wife thinks I should do this instead of buying a boat setup already right now. Anyway we are jus gonna use it to go up and down river hopefully, and maybe go to the lake every once and awhile during season. I found some hope up parts on the web and I think we'll do that and try and get around 3-4 more horse out of it. Both of us way 160-190 a piece, any more thoughts are much appreciated and are always considered. Thanks for all the responses!!!!!

It will push it.Weight is going to be the problem.Wont be no speed demon buy should work.My 1st boat with a longtail did 6mph.Beat the shit out of walking.

or swimming!!!

Sounds like you will be swimming. 2 guys and a dog in a 12x36..... not too stable. If you cough you might capsize.

Only one way to find out

Put a deck on the front and weld on side extensions to keep the water out, or put a top on it like the phowler prowler sneakboats. That way if water gets over the sides/bow it still won't be able to get in the boat.

or just get a bigger boat...

Then there's that

Thanks guys for all the help! I think I'm gonna try it cause like you guys said only one way to really know! And if the long tail I build works out, I got a trick up my sleeve.