Exhaust manifold for a 90

[wayne]

I might need a passenger side exhaust manifold for my 90 It would be GM 14093654 RH 7. I believe 89 to 91 will work as long as it does not have the smog pump holes. I will know deffinately in a few days when I pull the engine if I need it but it looks like mine has a crack in it. Let me know what you got.

 

[4X4HIGH]

Be careful buying a used manifold as they are notorious for shrinking and then you need to use a manifold spreader to install them again and that will just stress the bolts and eventually break them or the manifold. I'll bet if you take your manifold off that it has shrank and the bolt holes no longer line up. I just removed mine from my 89 blazer and had this same issue with the passenger side and the manifold is cracked as well. You can buy them new after market and not to expensive.

 

[dyeager535]

Be careful buying a used manifold as they are notorious for shrinking and then you need to use a manifold spreader to install them again and that will just stress the bolts and eventually break them or the manifold. I'll bet if you take your manifold off that it has shrank and the bolt holes no longer line up.

Any reason the bolt holes can't simply be drilled a bit oversized to solve the problem? I've got some manifolds in the garage that are probably correct, but I've run into the shrunk manifold problem before and can't guarantee them.

It would seem that drilling the holes slightly oversize (only one hole has ever been the problem IME though) would easily solve the problem, and unless gasket matched to the heads, probably not hurt flow enough to worry about.

Not running manifolds anymore, or I'd try it myself.

 

[4X4HIGH]

Any reason the bolt holes can't simply be drilled a bit oversized to solve the problem? I've got some manifolds in the garage that are probably correct, but I've run into the shrunk manifold problem before and can't guarantee them.

It would seem that drilling the holes slightly oversize (only one hole has ever been the problem IME though) would easily solve the problem, and unless gasket matched to the heads, probably not hurt flow enough to worry about.

Not running manifolds anymore, or I'd try it myself.

That can sometimes be done. In my case once i pulled the manifolds and went to see how badly they had shrunk i quickly discovered that each end had shrunk 3/8". There is no way you could drill out the holes to make them work again. There just isn't enough material in the manifold to do it then have a bolt still able to clamp the manifold.