what front suspension drop amount do i have
 

so with my 72, previous owner lowered it, the rear springs I was able to get the numbers cpp 603-5 , which have found is a 5" drop spring for the rear from CPP. as im trying to do mathematics for fitting 20/22s and what will fit and where it will sit in the fenderwell, with a 255/50r17 tire on a 17x8 rim, both tires sit 26.5 inches tall from the ground (tire calcs show 27 for some reason) , and both front and rear fenderwells sit at 28.5 for the bottom of the center, so the truck sits level with no rake according to center fender lip measurements. would that be a 5 in drop in the front or are they less in the front since the motor ? thanks

Re: what front suspension drop amount do i have
 

I believe you have a 3/5 drop if I remember correctly beings the original height was 2 inches higher in the back. So with it having a 2 inch rake stock, to become level with a 5 inch drop spring, you'd need 3 inch drop in the front.

As for info on the 20/22 wheel size, I don't have a clue.