TTI Exhaust

Well, I have a 2.5 inch TTI X-pipe system and TTI headers on my 67 Barracuda with a mild 360 (stock replacement cast pistons .090 in the hole at TDC, MP 761 cam with 270/272 duration and .450/.455 lift, unported Indy LAX heads, RPM Air Gap intake, 3310 Holley, 3.55 gears, 11 inch converter, Nitto 275/60/15 drag radials. Ran 13 zeros at 106 through the mufflers last spring.

How much faster would it be with 3 inch exhaust system? I'm thinking a better converter and a hotter cam would make more difference than a 3 inch exhaust system, but I obviously have not tried it to see. Yet.