Converting it to road rally car? If its a road rally car, pinto allowed, bike carbs, yes, but only 2 chokes are allowed to work, arches are a no, seats and harnesses don't matter, but the interior needs to be there in full. If its a stage car, you'll need to have in date seast and harnesses for some events, but smaller single venues normally let you run out dated stuff provided the scrutineer thinks they are safe.