I've been scouring the web for the plank sizes of the 7 boards that make up a 46 1/2 ton shortbed.

I've found that they are either 77 1/8" long or 76 3/4" long. Which is correct?

Are they supposed to be 5/8" thick or 3/4" thick?

How wide is each board?

How deep and wide is the groove along the edge for the bed strips?

I've purchased a Mar-K box kit but did not think it was worth it for the wood as we have plenty of it up here in Canada. I figure I'd make my own but I do not know the exact measurements. Any assistance is always appreciated!