You can switch your existing cassette to new wheels, s long as the new wheels are campy 8 speed compatible.

However, it’s like the cassette needs replacing anyway if it’s on a 30 year old bike, depending on when the cassette was last replaced and how the bike has been maintained.

If the goal is to avoid the cost of $60 tubulars, buying a new wheelset isn’t going to be cost effective. Not only will the cheapest new wheels cost a multiple of that, the tools to switch out he cassette will cost close to $60.

Your most cost effective answer may be to sell the bike, and buy another used bike with clincher tires.

Or learn how to repair tubular tires.