273 4 barrel manifold questions

Thinking of putting a 4 barrel on my 67 273, 2 barrel Going to a swap meet next weekend and wondering if anybody can give me the numbers to look for on a cast iron manifold, will also be looking for a edelbrock ld4b. Not very hopeful about finding something, but you never know, besides it gives me an excuse to go to the swap meet.
Thanks
Aaron

Oop's my bad. I found casting numbers in the tech section.