It's always all or nothing with true clutch heads and I'm one of them. That being said you can get a really good HP (50 HP) boost by simply adding a mild cam with a new set of hyd lifters and pushrods as a must. A cheapset will run you around $200  from Summit but a 100+ HP gain is going to cost you. Like everyone said if you want a jump that high the rest of the engine will need to support it. If cash is a problem the 50 HP solution will get you excited about your Vette again. Good Luck with convincing Karen.