So I've been cleaning the underside of the 67 body for the last couple of days. Basically just scraping off the greese/oil and road grime so far. It almost looks like it's got the trunk paint rather than any kind of undercoat. Not sure what kind of finish I want to put on there when I get to it. Chassis black, rubber bed liner type spray or try to copy the original color/finish( not sure I can find it).

Are you doing the entire underside or just trunk and rear wheel wells?

Try some of that "green" degreaser. Works awesome.

FireBob, if you want a good durable finish - but not original - check out Rustoleum hammered black or gray paint. I got it at Lowes by the quart and used a brush to apply. That stuff is tuff as nails! I used two coats. And very reasonable cost. I used this on my Plymouth.

On our bird I had the underside sprayed with the rubber type truck bedliner. Wish I hadn't. Just because... no reason other than that, I just wish we hadn't.

There are some more expensive options available, "Chassis Black" comes to mind, I think available at Eastwood or auto paint shops.
Cal

I will do the whole under side of the body from firewall to rear valance. I was thinking the rubber bed liner coating would help deaden some of the road noise and maybe be more durable but I do like the clean look of just the chassis black.

If you do it stock then seal it with epoxy and top coat with car color...or use black in urethane. Spray it! brushing on ACE hardware paint ... no

I'll have to wait till it's clean to see exactly what the color looks like. Hard to tell yet but it looks a bit like the aqua/gray trunk paint. Not exactly the splatter paint but a smaller partical mixture color( hard to explain). When I get it clean I'll take a good pic and post it. The only paint left under their is in the protected area like up in the tunnel where it got covered with oil and greese and never got worn away or rusted. Should be enough to get a good idea. Maybe I'll make a run at the paint store and see if they can get some or make it.

X2, epoxy then single stage urethane, for sound barrier put mat down under carpet.

I as well had multiple colors after removing undercoating, notice the original Bronze body color.

Wow, I am learning something here. I completely stripped our '67 down. That was about 10-12 years ago, but I do not recall any of the original paint color on the underside, anywhere - other than what I might have considered overspray.
Cal

I did my coupe years ago. Just grease and crap and rust. I did the floor on my vert a few years ago and after the grease was removed I found the original paint there. It's like they quickly spray it to seal the factory primer. Top coat for color, but just barely.

Man that pic is strange. I'm not liking the look of that stuff. You might want to blast that sucker. Are you restoring the whole car?

It almost looks like they sprayed some of the undercarriage with that robust asphalt coating GM used at the factory in the four wheel wells to deaden sound and resist stone chips.

My 69 rear wheels and body rails looked like that also sprayed heavy with undercoating which appears to factory and it also had the gold body paint overspray under it just the rear only was like that also the floor pans had paint on them and in some places looked like a Grayish green primer or sealer with some black paint and gold overspray from the body color

Yup, doing the whole car. Haven't gotten as far as wheel wells yet. I assume they have that thick factory undercoating. We'll see how burned out i am when I get to that point. I know one outer wheelhouse needs replacing in the back.

Closeup of the factory spray on road guard.

Huh! Doesn't look like this underside ever had any of that "road guard" material applied. Appears to be all paint and rust under the grime.

[img]https://firstgenfirebird.org/forums/ubbthreads.php/ubb/download/Number/17263/filename/bdf_mac - 2032.jpg[/img]

Maybe you should blast the whole body. Put it on a roto. Made most jobs much easier. The professionals will tell you to strip it down to the metal and see what you have (at the beginning of the project).

Notice all the blue on the floor pan (top & bottom).

I thought about a roteserie but I didn't want to do all the bracing. And besides I'm limited on space in the driveway. I thought about getting it dipped but I'm scared about what would be left when I got it back.

I got a lot of my parts dipped. Turned out awesome. They did not have a tank deep enough for an entire car. You have to prime them immediately after dipping process completed. All the parts shown on this thread were dipped, primed with epoxy and then painted with top coat;

The roto makes many jobs much easier. They don't take up more space. You need to assess what needs to be done. You may end up blasting the entire car anyways. Look at my B4 pic. Car does not look like it needs a restoration at all. Dig deeper and currently it' stripped down and epoxied.

Roto will cost your $1000-$1500. Sell it when your done for half price and that's a very cheap tool to buy.