Does it really make THAT much difference? 600...500...? Anything that runs on a 500 will run on a 600...now if it would take a 750 down to 5/600, THAT might be useful.
Think mileage helper or a easier way to run dual quads with what you have. In example, a Edelbrock D-66/64 dual plane dual quad on a 340/360 could use 2-500's. OR 2 400's on a 318/340/360.
