Exhaust manifold outlet diameter

[TruckA]

I should have measured this when the engine was out, but can anyone measure or do you know the diameter of the exhaust outlet on the SD22 exhaust manifold? I'm buying some flanges soon.

Thanks,

David

[pbknowles]

The I.D. of the hole itself is 1-3/4 inches, but it tapers out to ~ 2-1/4 inches. The stock head pipe has a formed on "bubble" that seals on the tapered part.

[TruckA]

Thanks for the detailed info. I'll try a 2.25" flange and see how it works out.