I found that out too. I used a March dual groove pulley set that they list for the fluid damper (10170 kit) but it was too shallow by about 3/8", so Andy sells a 3/8" spacer (AR140?) that worked, but I had to use longer pulley bolts (ARP 612-1500 1.5" long). The result was close, I think the crank pulley aligned with the power steering pulley, but the water pump pulley needed a thin shim to get everything aligned correctly. On the plus side, I have never thrown a belt yet even when hitting 7,200 RPM.