Need help identifying a P30 exhaust part

[Ryan7361]

What is the correct name of the part bolted between the pieces of exhaust pipe? It is cracked and crumbling, I would like to replace it. It’s linkage is controlled by that vacuum valve. It’s on a 1987 P30.

[c farmer]

Looks like a exhaust brake.

[SStockhaus]

Heat Riser https://www.google.com/search?q=heat...=firefox-b-1-m

[D Gardiner]

That piece is used to restrict exhaust flow during cold engine warm-up. The exhaust restrictions helps to heat up the intake manifold and help keep the fuel atomized. If your engine warms up and runs good, you can remove it at an exhaust shop and either have a short pipe fitted, have a bypass install or weld in a new down pipe.
This also is only if your state does not require an emissions inspection.

[Soppy]

It's a Heat Riser Valve used to direct the exhaust gasses through a passage in the intake manifold to speed up engine warm up. Once the engine warms up , the valve opens. It will not harm the engine to run it with the valve removed.
A more common problem is the valve sticks closed and overheats the intake manifold causing a loss in power.

[Jyrocharlie]

It's also a common problem the gasket burns out. I removed that part and bolted the pipes together, there was enough pipe to do it. I used a gasket that was flat on one side and a cone on the other. Do this mod to make plug wires and that right side exhaust run cooler. This is a chevy factory service bulletin for a 454 in a motorhome: