63 gmc suspension

[jnova67]

Im working on a 63 3/4 ton gmc and getting ready to swap in a 1980 c10 front and rear suspension. Im planning to unbolt the crossmembers out of both and ive read I may have to add a couple holes or move a couple which isn't a big deal. The frame on the 80 was cut off after the steering box so im wondering if the 80 steering box will bolt up in the same location as the 63 or is it in a different location? Is there anything that I should be ready for (surprises)? Im also putting a LS in it and was planning on using the 80 frame mounts and motor mounts (I will need an adapter for the LS), I figure if stuff doesn't line up I can drill new holes there too. On the rear I was planning to c-notch and do a flip kit and im hoping that'll get me the ride height im looking for. Im planning a 4-5" drop in front and would like to get it level or slightly higher in the rear so probably a 5-6" drop in the rear. Main concern now is the front suspension and the steering box location since I don't have anything to go off of. thanks