I second 52Carl's advice on using a short length of windlace, just an inch or two long. You will discover there are 5 or 6 pinch spots on each side and you should open them up with a screwdriver or other tool. I think at the factory the channel was wide open, easy to slide in the windlace, and then after it was in place, a half dozen wacks with a mallet it was secured. If you don't find all the pinch spots you will never get it in. My experience is with a 50 Chevy COE built in Kansas City.
Also, there is a gap in the channel at the top rear, so start one end at the top rear to go down the backside and the other end start forward. It also helps to have another pair of hands to push/pull the windlace through and keep it lubed with that lubricant I know you keep in the medicine cabinet.
Good Luck and let us know how it goes.
Kent
