1987 Exhaust manifold

[sandawgk5]

Does anyone know the stock pipe size from the manifold flange down to the Y in the y-pipe? I am looking at redoing my Ypipe to get some shaft clearance and tuck it up a little bit and I need to know what size mandrel bends to buy so I can fab it up. I want to go with 2.5" so should I just get new flanges and go from there or will 2.5 not bolt up to the manifold outlet?

Thanks

Ira