ok just a question rear widebody fenders on an fc good or bad idea to fill with spray foam gap filler to take some of the flex out?

 

I'm not sure what gap your talking about but if it is just the gap between the rear quarterpanels and the overfenders I wouldn't.

 

Generally when one installs over fenders the stock fenders need to be trimmed up for tire clearance. I have a writeup in the first gen archives on how to do that. Search for threads started under my user name there. After I installed the over fenders I made a new liner that filled in the space from the newly trimmed inner fender to the over fender. I used rolled aluminum for the liner, it came from the roofing section of the local building center.

I don't recommend foam as it often expands too much and can distort the over fender. If your over fenders are fiberglass, stiffen them up by adding a couple more layers of fiberglass.

 

Also if you foamed them it would retain moisture and cause loads of problems with the stock body with out being visible.

 

My rear quarter panels were bonded on, no foam is necessary and the gap is smaller than you think. In fact normal body filler was used and then totally blended in to look like as if it was there from the start. I would also recommend cutting the inner arch prior to this going on to accomodate the larger width wheel. It looks better as well. I did mine after and it cost me more to cut it out with a plasma cutter.

 

Thanks guys any more info or pics of cutting the inner arch

 

I told you how to search for my 'How To' thread but since I'm feeling generous tonight, here's the link to it:

https://www.rx7club.com/1st-gen-archive-71/body-how-modify-wheel-wells-fender-flares-733340/

 

man... those tails look mean! cherry car. lol sorry to get off subject