For that matter, there are any number of reputable engine builders who have built engines with ported LA heads. So why aren't they creating templates and selling them? Probably the same reason MP/DC discontinued them, you can buy newer, better flowing heads for close to the same cost of rebuilding and porting a set of old iron dogs.

I'd have to dig up some old catalogs and look at the the numbers, but I seem to recall that stock Magnum R/T heads would outflow a set of ported LA heads right out of the box.