[oldman3]

Main52, hope I don't come across as a "smart a$$", but I can't find anywhere in the PDF, where it says "flatten top of frame", for spring towers. I could be wrong if I am, I'm sorry.
I just want to help if I can.

Item #3 on both pdf's, do refer to boxing plates to frame, "grind frame rails edge flat so plates lay flat"

Item #6 on speedway pdf, refers to grinding the spring towers to fit the frame.

Both drawings show where the frame curves down in the front, the spring towers sides are straight and would need to match the frame.

I have a couple pics to show what they are talking about. First pic show boxing plate in place with the part of frame that needs to be removed. The second pic shows boxing plate in place with part cut out and top and both edges of frame ground flat to plate.