Ok here is the deal. I am installing 2 new goodmark rear frame rails on my 1967 firebird. I put in the pass. side first so I would have the driver side to get factory measurements from. Here is the problem, I found frame dimesions from several sources, The first was wrong because it was an inch wider between rear shackle measuring points. So I set the pass rear to the 42 7/8 inches. The front I bolted in with the spring pocket. The spring pocket has a notched and it lined up perfic when all 3 bolts in the spring eye pocket were tightened. So i made a couple of spot welds to hold in place. The front factory gauge hole on my driver side was rusted out so i couldnt take a measurment. I removed the driver side rail and installed the same way. Now when i take a measurment at the front master gauge holes it is not at the 33 1/2 inches center to center. The spring pockets are as far over as they will go to each side. If i take a measurment from the center outside edge of the gauge holes i get the 33 1/2. And if i do center to center it is 33 inches. That would be exactly .25 inch. for each rail to have to move out. And they cant because the pockets are tight to the outer sides and the pocket notches cant go over any further. So is the 33 1/2 inch a typo?? I cant find any info anyware on this. Any input or info would be greatly appriceated.
Thank you for the replies. I think i have figured out.The leaf spring front eye pockets I installed are aftermarket reproductions I purchased five years ago and put on a shelf until i could afford to get to this part of car project. I compared the new pockets with my old one i had left. There is a quarter inch differance on the outside edge that touches the rocker panel. I installed my old one and the frame rail moved the quarter inch I need to the out side. So If I do the same for the other side it should give me the factory measurment. Here is the kicker I looked at 4 differant companies selling the front eye pockets. Goodmark,classic industries,yearone,tamaraz. The only one out of the four with the correct pockets was classicindustries. The other three looked like the ones I currantly have that are over by a quarter inch. So I will see if the classicindustries ones are correct or not when i recive them.