It seems weird that Koffel has never tooled up an RB version of that intake manifold. Those heads have been around for 30 years and the RB block is 10x more popular than the B block. They would've paid for the tooling many times over by now.
They do and they have, on a very limited basis with no plans to mass produce them or likely even making any limited runs of them.
"I am not ashamed to confess I am ignorant of what I do not know."
