This is a set from KGTrimning, I don't recall seeing part numbers on them but I don't think they are built just for the Volvo application - perhaps just bored and rebushed?. They look exactly like the ones on John Parker's website, red anodized aluminum. They don't need special pushrods - I am using a set of tubular rods and IPD - S/B Chevy lifters.

The aluminum bridge replaces the two small perches that the rocker shaft normally sits on with a large aluminum structure that fastens underneath the valve cover as well as the two original bolts and supports the rocker shaft all along it's length. Dampens vibration and prevents flex as each valve opens, supposedly.