I have the PY 2.5 inch X-pipe system for headers on my '67 coupe.
In general, the install was pretty easy. With the narrowed 'X' that they designed for the Firebird, I was able to tuck the pipes up into the tunnel.
The one issue I have is with the tail pipes over the axle. To me it appears that the bend is too large, so I can't tuck the tail pipes up high enough for the muffler outlet to sit level with the inlet. The mufflers are offset inlet and outlet. With the inlet pipes positioned up high in the driveshaft tunnel, the mufflers can be placed close to the floor. The tail pipes go up too high over the axle and the muffler has to be rotated (around the inlet pipe) so the outlet is about 2 inches lower than the inlet in order for the tail pipe to line up with the outlet. That reduces the ground clearance and makes the mufflers the low point. At some point, I want to re-work the bend over the axle.
I hope this description makes some sense. I can take and post some pictures if anyone wants.
