I put long tube Hedmans on the 360 in my D200, the stock manifolds were cracked to hell and leaked really bad (noisy). I wanted to see if it would make a difference and they were affordable. Already had true dual exhaust. Sure enough, throttle response improved and needed less throttle for the same acceleration as before. WOT performance didn't improve much thanks to the stock 2-bbl cam but there were still noticeable gains. On a truck that does truck stuff (towing and hauling) extra part-throttle performance is nice to have.