I have a pair of 4 bolt manifolds that have been sand blasted clean. They are the 4 bolt short type that fit 1.7 and 1.8L heads. The shorter manifolds give better lower end performance. They also have a 3/8" NPT port for a balance tube.
Opening at the top is 47mm and at the bottom is 35mm. Last time I checked these ran about $75-$90 a pair new. Asking $45 shipped.

Bruce