i hope the steps i have are big enough for my 582 i'll be running 1/8 mostly but i wounder what a 2 1/2 primary with a 5 inch merge collector would act like i bet too big down low(in the 1/8)and great at the big end(in the 1/4)the motor seamed real responsive with a 2 1/4 header on it last year BUT never made it to a 1/4 track or had a chance to put the steps on it to see the difference. jeff