I have seen adapters advertised that are used to convert a non-TBI engine so you can you the 2 barrel GM throttle body. I've never seen one installed, but its a fairly common conversion. I think you could install a stock GM intake on the old heads and just use the adapter like this. http://www.summitracing.com/parts/TRD-2211/
I've also seen several folks suggest that you can redrill the center holes in the intake, but its usually the opposite of what you need (they usually want to put an old intake on newer heads).