1960 GMC K1000 4x4

[McMurphy]

Originally Posted by piratexpress1369a

what are these parts after the muffler?

Those are actually ~before~ the mufflers and are called exhaust dumps.
Like Kro said, they are so you can run basically straight headers and bypass your mufflers which rob you of horsepower.
They make electric dump doors too, FYI so from within the cabin, if you care to you can hit a switch and romp on it !!!

I want to install that set up in my wife's 72 LeMans so she can trick the young boys at the stop light.... ummmm .... oops .... I mean not do anything illegal or .....
Heheh I am going to shut up now.