i do it to keep the heat soak down on alum intakes with alum carbs

yes it will make the exhast note a tad different

aftyer a 40 mile drive I can not keep hands on the intake anywhere but the carb is like warm

cross over blocked,1" stacked alum plate/gasket heat disapater on mine

cured all the hot start problems,and the fuel perking stop

yes,it is for a much cooler intake charge,cooler denser air charge = more HP and is/was the main reason its done,now it mainly for heat soak on a daily driver

had a old timer tell me it was to replace the H pipe found on the mid 60s to late 70s exhast systems.

evens out the exhast pulse like the H pipe does.

now if that is true or not I have no idea,sound good though