These parts are rarely available in this complete and near NOS condition. These are the performance exhaust manifolds for 61-64 389 and 421 Cats and Bonnes and Grand Prix. Original to the 425A hi-horse cars. They are early take offs... Before pn plates were added to the tooling (537454 and 537455).
My estimation is these are 61-62 units. The heat riser is frozen in fully open position. No cracks or repairs anywhere. The LH casting has what appears in photos as a crack but it is not. It is superficial line on surface of the casting.
Flanges, starter pipes, circular gaskets and studs/ss nuts and the elbow. The item "1961-1964 PONTIAC 425a EXHAUST MANIFOLDS 389HO 421HO CATALINA BONNEVILLE VENTURA" is in sale since Tuesday, January 15, 2019. This item is in the category "eBay Motors\Parts & Accessories\Vintage Car & Truck Parts\Exhaust". The seller is "pure-poncho" and is located in Round Lake, Illinois.This item can be shipped worldwide.