are there any readily available pipes that can bolt in to the stock location? or should i just have a shop cut / weld a piece.  also , the 81 does not have an O2 sensor as part of its CCC correct? is the computer on the 81 just for timing  , etc 

so my vette has an exhaust leak... sounds like on the right side.  i was going to delete the cat and change the mufflers anyhow. after comparing cost of having a cat delete pipe fab'd up and mufflers cut out and welded in , i decided to pull the trigger on the magnaflow dual exhaust system from CC. the original cat it most likely toast anyhow. my question is now what to do with the AIR system and line. can i just cut the line where it led into the cat and leave it there? its just fresh air right?

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If you are going that route, it would prolly be best to remove the rest of the smog system, and be done with it. You could just cut and plug the line to the cat, but then you have an air pump pumping air to...nowhere. If you simply remove the air pump drive belt, now you create a scenario where the plastic check valves/diverter valves, and other components could overheat/melt. Quickest way to eliminate the system other than removing all of it, is to remove the check valves from the exhaust manifolds, and cap the valves themselves, and remove the belt from the air pump.

thanks , so if its just air thats getting blown out of that pipe, can i just let it blow? theres no exhaust gasses or anything coming out of that line to the cat right?

Or air is blown into it...

ok , so either way , just leaving it open shouldnt be detrimental.  ill have the true dual exhaust in there with the magnaflows soon

No...that is NOT just fresh air being blown into the cat. There are exhaust gases in the mix that come from the exhaust manifold, that are mixed with fresh air(diluted) inside the air pump, and then piped into the cat to be burned. It is these gases that help "ignite" the unburned fuel in the cat to make it work properly. Easiest thing to do would be to remove the check valves, and find a cap to put onto the pipes on the manifold....and remove the belt from the air pump. This would completely eliminate a functioning system, and you would have no issues.

I'd remove the whole air pump system and use pipe plugs on the exhaust manifold. 

i appreciate the definitive answer on this. i think i will try to go the route of removing the system. this is a nice driver , not a concours restoration.  from anybody that has done this, do you have an actual suggestion for the pipe cap? does it have to be welded ? etc

or i can see if the shop can tie the piping into the new exhaust pipe with some cut / weld