I didn't install a new pilot bearing in my 37. I had also installed a new one not too long ago and found that the input shaft "snoot" was exactly the same diameter dimension on the T-5 as the input shaft "snoot" on the stock transmission. The "snoot" was longer on the T-5 and that was exactly what I needed to make the installation work correctly with a 1/2" thick adapter plate. I would think the GMC would be the same.
Joe
