Whats the difference???

I wouldn't rhino-line. That stuff is made for truck beds...

It's good stuff, but there are better alternatives out there. Por15 for example.

Powder coat would be best, but you know that you have to bake the part (in this case your whole car) in an oven right? If you have the car stripped to the point where it can be baked, then I think that's the way to go.

My 65 has a spray on undercoating...

under it, and I`d love to slap the C#@P outta whoever done it. Everytime I go to get a nut or bolt loose I have to clean the gunk off of it before I can get a wrench or socket on it.... Its nasty, I`ve spent bunch of hours cleaning this junk off, I wouldn`t reccomend this method.

Would like to know more about this por15 though. I`m like you, I need to put something back on it, it may actually get wet one of these days by accident....

My 67 fb is stripped to nothing and it is getting blasted and black epoxied inside, outside and undercarriage. I guess it depends on who you can find to do it and how much. I think any of the methods, powdercoat, epoxy, por 15 all have to be much better than they came from the factory

I agree with mikec35, powdercoating would be at the top of the list, then epoxy primer, then por15 or other similar products. I spray epoxy primer on everything that I strip the paint off of.

Well, I'm doing the same thing to my 67 coupe.
I have sandblasted the underside, repaired the floors and a few other spots, then used a product called chassis saver from magnet paints. http://magnetpaints.com/underbody.asp

I'm not associated with them, just impressed with their product.
I bought 2 gallons of this stuff, 1 silver and 1 gloss black.
I used a brush and coated the entire bottom with the silver and when I'm finally done blasting and patching, I'm going to spray the black over the top of the silver.
This will build up a fairly thick layer and help stop the rust.
They claim you can paint over rust, but is needs to be at least wire brushed good first.
I took and old piece of floor pan that looked like swiss cheese.
Used a hand brush and cleaned the rust off as best I could.
Then I took a brush and put 1 coat of silver on and let dry.
It seems to hold up really well, and barely come off even when scraped with a scraper.
Not trying to sell anybody on this product, just trying to give a review of what I have observed.
Hope this helps
Allen