i have an 85 iroc-z with a 305 T.P.I. engine. it has a 700-r4 auto trans. i was just wondering what the difference between a stock gear ratio and one you buy from summit. if i were to put say 3.73 ratio gears in my car, what would i be achieving? better launches? more torque? i have no idea. and is a 3.73 ratio good for a mildy modified 305?(headers,catback,maf,k&n) if so, what size tires would go with the new gears?