Questions out of curiosity, given my recent problem with corrosion post ...

I noticed that you cut away chasis panels and treated the interior. As well, you welded on nuts to the removed panels.

How much rust did you find in the boxed in sections that you opened up?

Certainly welded nuts are a strong way of attaching bolts to a panel. Did you consider installing Rivnuts?

Interested to know

Surprisingly not that much rust. The plates were mostly beat up from people jacking on them. At that points welding in nuts were as easy as anything. The rest will be nut tabs.



I added a support piece to the channel, cut groves for drainage and even added drain holes.



The replacement plate is heavier plate.



The last step before beginning final body work on the car is to spray the inside of every channel.

FWIW Larry Stock shaped and blended the underside of his '72 race car for the recent Fun Rally event. He then had to raise the rear ride height by an inch as the additional downforce was causing the rear to scrape all the way around the track.

This was his confirmation that there is a lot to be gained from a belly pan/underside aero mods and diffusers

Julian

Interesting. I figured do it now while on a roto or not at all.

The 3 aluminum sheets welded together and side pieces on front welded on.

Nut plates added. Pan will be bolted on in 34 locations. Should be snug.

Looking good Gary!

It's not great but it's done. I need to clean the edges here and there but I won't need to crawl under the car to do so now. It's ready to bolt up. I can set it aside and move forward now.

Looking great! You going to powdercoat it before bolting on? That is what the proior owner said he did to my Group 4, although I am not sure if it is or not. Seems it would last longer that way, no?

This all looks interesting? But like the Racing Drag Boats that have flat bottoms, sometimes when they catch some air they seem to want to take flight! And that would wreck your day!

Nice work Gary! Keep the pics coming.

This is something I've been thinking about for a few years. I've seen Jan's partial treatment, but always thought that a pure flat bottom would not improve handling and as Cuvee points out, be quite dangerous at high speeds.

But a well planned ducted flat bottom leading to a rear diffuser could be a great improvement - even when not at race speeds. Joules, do you have any pics of Larry Stock's setup?