Can anyone help me identify these axles? I just recently bought a 81 Z28 that was built, probably late 90s, early 2000s, for the old NMCA EZ Street class and grudge racing. The gentleman that I bought the car from knows virtually nothing about it. He took it in on a trade, drove it once, it terrified him, and he parked it. The axle ends appear to be factory Ford 31 spline. The rear is a factory Ford 9" that has been fully braced and had fill plug and drain plug added. The Camaro is mini-tubbed, so I suppose that the axles/rear may have shortened. The rear wheels are 15 x 10 with a 6.5 backspace and the slicks are 29 x 12. They are tucked inside the fender lip. I have just never seen drum brake registers this thick. There also appears to be a color change where you would suspect a factory drum brake register would end. However, there does not appear to be weld marks there and there are no bolts behind the flange.This is the passenger side. The driver's side looks almost the same, but the brake register is slightly less thick. The wheel studs are screw in, but are the bolt style and are tacked welded to the back of the flange. I am planning on upgrading the axles and spool to 35 spline, I'm just curious what these are. I don't know that I've ever seen a factory axle with lightening holes in additional to the access hole. Odd that the flange only has 3 of them, also. Any help would be awesome!