Did a little research on Z28 exhaust:
42566 y pipe 67.99
21598 muffler 42.99 each.
43744 and 43745 are 24.79 each
43662 39.79
43663 33.99
There are other pipes listed for "earler" versions of this system at about the same price. The 21907 muffler that you have posted about is the stock 1 pipe in and 2 pipe out for Camaros and Novas of that era. When the Z28 came back out in 1977, I bought one. ( I was only 2 yrs old at the time) This exhaust system was the only real change to the engine, the rest of the engine was stock LM1. The exhaust added ~20 hp over the system that you posted parts for. At the time I took 2 stock exhaust pipes from a Chevelle and ran them from the manifolds to the mufflers,getting rid of both y pipes and the converter. Believe it or not they fit perfectly and I ended up with a true dual exhaust system. I would recomend that you buy the Z28 system starting at the y pipe and have the shop make you a 1 piece 2 1/2 pipe to crossover and hook up to the y pipe. The shop may even be able to get the pipes cheaper than you can. At the very least get the y pipe and go from there. I have been told that the 292 manifold outlet is in the same place as our 1bbl intergrated head. If someone could verify this (TLowe?) then everything would bolt up when the head was changed to non intergrated. Jay 6155
With the cooling system finished this week, my next project may be moving along to the ignition system and upgrading the coil, cap/rotor, and plug wires. But I'm thinking about the exhaust and maybe trying the Z28 cat-back setup. Attaching it to my existing 2.25" header pipe like was suggested with a pipe going from 2.25" with adapter to the 2.5" on the Y-pipe. Then when I make the exhaust manifold swap to the 292 HD 2.5" one, I can just hook the 2.25" header pipe to it and get it running down to the exhaust shop to replace everything from the Y-pipe forward with 2.5".
