original exhaust size

[aaronz28]

Anyone know for sure the correct exhaust pipe size for Z28 cars?

i currently have a Gardner Chambered system on my car which I believe are 2 inch...... the problem is that the little locator piece (which is the small piece of pipe that holds the composite gasket in place (at the manifold)   that piece brings the ID of the pipe down to 1 3/4 before going into the headpipe... (talk about a restriction for a high winding motor)

i see that many suppliers state that there is a 2.25 system that is for SS350 and 302 Z28 cars.....

did the small block and bigblock cars really have the same diameter exhaust pipes? with just a change at the manifold?

Thanks

Aaron

[Stillwater Camaro]

2.25 was the original size and I believe the Gardner is an exact duplicate of it. That spec measurement is OD, so the ID is close to 2", if that is where you are measuring it at. If I remember right that gasket holder can be cut back to very near the lip were the ring sits and eliminates most of the restriction you are talking about. You need to be careful to tighten the 3 studs evenly to prevent the gasket from getting cockeyed and leaking. The extra length that seats in the head pipe allowed the factory workers to do it quickly without as much attention to detail.

[JohnZ]

You need to be careful to tighten the 3 studs evenly to prevent the gasket from getting cockeyed and leaking. The extra length that seats in the head pipe allowed the factory workers to do it quickly without as much attention to detail.

The "sleeve" or "extension" that fits the I.D. of the "donut" isn't there just as an assembly aid; it reinforces the I.D. of the donut so it doesn't disintegrate when the studs are tightened. If you assemble the donut without the extension, the donut will fragment and disappear in short order, causing a massive exhaust leak.

[Dave69x33]

Does Gardner or anyone else sell the extension sleeves?

[aaronz28]

its just a small piece of pipe.. any exhaust shop can make them.
thanks

aaron