My 68 vert w/ a 302 has 20" glasspacks and tri-ys. That was fine until I put in a more aggressive cam (.48 lift, 210 duration - a torque cam, but still much louder than stock). Now the car is too loud for me. Two questions: 1. Should my new system have 2 1/4 inch piping or a different size? 2. How can I get a feel for the sound difference between the Flowmaster Delta 40 and Delta 50? Other mufflers to consider?