Rear trailing arm question

[72kool]

does anybody know if these will work on our trucks?

http://www.ebay.com/itm/Nascar-Truck...tWZN6I&vxp=mtr

i found these and they are not a bad price after shipping to my door compared to other vendors and used oem that i have found. from what i understand from the ad, they are 45 inches from the center rear hole to the center of the bushing. I want to use these on my '72 gmc C20. would these fit? also would they need any strengthening to be used on my 3/4 ton? they look to be stronger than factory in my opinion