Originally Posted By: Mr. Mustard
I own a 1977 292 G20 Sportvan with a major exhaust leak. Somewhere on this forum or another I was read that you cam switch manifolds on the 250/292.

So when a 1974 Nova with a 250 intake/exhaust and carb for a very resonable price I bought it.

Is is okay do downgrade manifolds?

If so I am having a hard time finding the right exhuast flange.
The 2 bolt style. It looks like your friend at 12 bolt has something that might work

http://www.12bolt.com/store/p154/Exh_Hardware_Kit.html

I found a site that may have what I need but the specs are not really meshing 2"13 or 2"25

http://www.mandrelbends.com/flanges-gaskets/exhaust-flanges.html?p=10

In the mean time the 292 exhaust manfold is totally shot as there is now some cracks as weel as I broke an ear off the face that leads to the tail pipe by over torqueing?

All that being said i am looking to replace the exhaust, but at the moment just broke to get her moving again.

I am on a serious budget, I had no plans to do any work to van van except change the oil,whaen i bought it 5 years ago but alas I can't let her go. Any advice you inliners coukd give would be greatly appreciated.

Mr. MUSTARD



If you can't afford the price of a replacement 292 exhaust manifold, and the '74 manifold is within your budget, then you can interchange the two. If you don't need the second intake manifold, I'm actually looking to pick up a factory manifold for the next stage of my project when I swap my integrated top end for a non-integrated top end. So I could buy it from you and help defray the cost some too.

Keep in mind will be changing the '77 2.25" outlet 292 manifold for the '74 2" outlet 250, so you will have some exhaust restriction. The new replacement 292 manifolds are 2.5", so it is actually an improvement if you put a 2.5" exhaust on it.

Your factory '77 header pipe will be at the wrong angle tho. The '74 and earlier manifolds angle backward so the 2" header pipe ran back under the linkage and down the driver's side of the car. In the '75 to '79 passenger cars, the 2.25" header pipe runs downward and then bends 90* under the oil pan to go out the passenger side to the catalytic converter. I have been looking for a diagram of the van exhaust in '74 and '77 and haven't found one yet. What is the path of your exhaust pipe when it leaves the manifold? Driver or passenger side?