chassis differences
 

Are there significant chassis differences between 70-73 cars and 74-89 cars? I'm thinking of backdating my SC to 73 RSR specs. If it requires major chassis mods, I'll stick to the IROC RSR...

front latch panel and rear cross member which mounts the reflector panel. Other than that front hood, fenders and both bumpers.

Check out Souk's back dating thread it should give you a good idea of what it will take.

Backdating can be done upto 89 as you stated. Do a search on this topic and it was discussed within the last few weeks. There might be some issues with the hood latch. Obviously you'll need bumpers and a whole front clip. Then it all comes down to details and how important are they to you? As an SC, you'll already have the rear flares going for you. Lights, chrome, and panels all cross over.

Look up some of SOUK's recent threads on this topic.

If you are going for "IROC RSR..." you are probably going for lightweight so OE fenders, hood, bumpers are not an issue to fit.
As said above it's nothing major.
Remember to post pics.

If you need some early oem fenders, I think there are a pair for sale here on site.

The plan is this... Back date to a long nose RSR. I'll be doing fiber bumps, fenders 9 and 11, hood and duck. Maybe doors.

What I'm not to sure about is the front fender mounting to the chassis properly at the nose. I know the back needs mods for the delete of the "porsche" reflector, just wondering about the front. Anyone have any pics of the front fender process on a pre 89 car??