hello, i know this might be a stupid question but here goes. i've been looking in the junkyards lately try'ng to find a 4412 carb off of the old fords. so far ive found a few carbs out there but im not sure how to identify which is the right ones to buy. some of them look like the fuel bowls look a little different with a power valve next to the fuel inlet and they dont say holley on them. if some of you guys could help me with some details on how to recognize the right carb without having to pay 300$ for a new one from the dealer i sure would appreciate any help. i wanna build a truck, im a pretty good welder and cant afford to pay 8-10g's for one already built. thanks kenny