I am changing my oil sucking 502 and 700R over to a 548 and 5 speed. The folks at Stahl Headers told me that my 2 1/2 exhaust is not quite big enough for the hp, that I need the 3" system. My question is this: I have lowered my 69 2", and I drag the headers and flange every now and then when I drive it hard. Do the 3" pipes hang down lower than the 2 1/2's? The headers will have a 4" flange. What do you boys think? Edd

i think you needed 3" with the 502, and definately need 3" with a 548. if you have 3" it still shouldn't hang down as low as your headers do.