Lay out the entire system beforehand to assess what youre in for. We ordered the kit (PN 17107) that fits 64-72 GM A-body cars like our LeMans, and chose more mellow-sounding mufflers (PN 52558). Theyre thicker than standard 50-series mufflers and more suited for big-displacement engines like our 0.060-over 455. The head pipes are designed for cars with headers, but a muffler shop could simply bend extra-long extensions to attach manifolds. Easily visible is the H-style crossover pipe that does a good job of balancing the engines raspiness. Two sets of tailpipes are included; we chose the turned down tails, which are virtually invisible once installed. Reducers arent included; ours came with the Dougs Headers we installed in The Great 455 Swap. Now that you know what youre getting into, raise the car as high as possible and support it with four jackstands. We suggest placing the rear stands under the axletubes so the rear suspension sits at ride height.