If a 3-2 intake from any company has 2 threaded bosses at the rear, usually sticking out the back it is an early version for 54-56 heads. So if it is an Edelbrock it would be a 543 or 553. Often one of these bosses is sawed off because it interferes with the 57 and later distributor.
Te next way to identify an Edelbrock is to feel inside the runner from the carb down to the plenum. If you feel a radius at the bottom of the passage it is a late 553 or a 573. The early manifolds were bored and had a square edge where the passages intersect.
You can also compare the gasket opening at the head to a known intake gasket. 543 will be tiny for 239 heads, 553 will be a close fit to a 55-56 gasket and a 573 will be very close to gasket matched to a 57 and later gasket
http://ford-y-block.com 20 miles east of San Diego, 20 miles north of Mexico
