early to late intake swap

i just bought a 1987 5.0 chevy motor with stock heads and i want 2 swap an intake off a 1974 350. if you look up intakes on jegs, summit etc. the part numbers cahnge from 87-95. is that just emissions bs or are the intakes not interchangable. they are not vortec heads just cast iron cyl heads.

In '87, the center bolt holes in the heads were canted, so an earlier intake won't work as a bolt-on. Read the installation instructions from Edelbrock....
http://static.summitracing.com/globa...0427012716.pdf