Technically speaking on C3s only 69s had sidepipes as an option, so if you have a 69 then its easy but many other year C3s have sidepipes. You may be ok just to put them on and when/if you get pulled over just tell the officer that they came standard on your vette, most people wouldnt know! keep ypur old exhaust just in case OR go through an engineer to approve the exhaust. Dont know if that helps!
