Headers ?
 

Welcome too the forum. If the manufacturer says they will fit then I would ask them why do they have the note that says they won't.

Thanks for your input 73shark, I’ve been reading the forum for some time before joining and I always look forward to your comments, you seem to be very knowledgeable about corvette (C3) matters. I bit the bullet and purchased them so I’ll keep you informed on the installation 👍

Good luck with your header install. Are you doing the custom welding work yourself or farming it out? I did my first headers under car and out the back with the stock exhaust. Then I picked up a set of side exhausts and modified them to connect up to the headers. But that had so many 90-degree bends that it turned out to be too restrictive. So then I went to Hooker nest of snakes side exhaust headers. When I get the car put back together, I will probably put the nest of snakes on for a while but plan on ultimately putting the factory side exhaust without headers on. I just need to complete the refinish of the side exhaust covers that I had replated.

My plan was to farm it out to a exhaust shop. Going with a dual exhaust with crossover. Haven’t decided on brand of mufflers yet , leaning towards magnaflow