I have aluminum riveted 1437 with a 15.5" reinforced transom. Going to be running a 20hp long shaft beavertail.

What should I do to the boat or do I really need anything?

Handrail? Pods? Etc......

I'd beef up that trnasom cause mud motors are hell on transoms

It's got a 3/4" piece of plywood bolted inside the lip that covers the entire transom......need more?

I'm talking about welded aluminum braces from the floor to the tansom

Oh...it has two of those already.

Do I really need a handrail? Seems like everyone else has one. Wasn't sure if that's a "nice to have" or a "need to have."

You talking about a grab handle? I would suggest it, them mud motors can jerk you around when you get in the nasty stuff

Now the next question......anyone know someone in SE Texas that can manufacture and weld one on for me for a relatively low price?

sure do bring it to Watson's or borel boat works, there are a handful of aluminum wleders i just can't think of all of them

Where are those located? I'm outside of Houston

hmmm i thought you were closer by the way you asked the question, if your in cypress they are about 1hour and 30 min. from you

I hunt and work all over SE Texas, so I don't mind a drive....

Watson is here in groves where i live, Borel is in orange Tx. which is about 25min from me, and iknow of some others

I bolted a piece of 3/8 aluminum about 30" wide and the same height as the transom and welded braces to the plate and then riveted the braces to the seat

The bracing is a good idea. I ran a rivetted 1436 w/18 HP GD LT for several years, and the 1/8" alum. U plate I slipped on the transom held up. Important standard equipment you should have: working kill switch w/lanyard (use it!), auto bilge (backup manual bilge pump), PFD's, running lights, flagpole and flag for visibility in the marsh, emergency lights and horn, flares, all necessary tools, spare fuses-fuel line-clamps-throttle-plugs-grease gun-prop.
Indicated mods: steelflex or gatorglide the hull bottom; tweak the throttle for a few hundred rpm gain; alum floor with closed cell flotation under floor and between ribs; hydroturf for surfaces; battery and/or gas tank placed in front; trollling motor bow/mount; DIY scissors blind for boat; synthetic oil and grease. Whew, that's a start.