1985 Chevy Truck th350c transmission problems

Transmission problem
1985 Chevy Truck V8 Two Wheel Drive Automatic? Miles

I'm a car nut and am by no means a novice. This is however my first attempt at rebuilding an automatic transmission. I've got an '85 Chevy truck with a 305 and a TH350C that I use primarily for scraping metal. It's moved countless tons for me, but I burnt the clutches trying to get up the scales at the scrap yard. (It had prior issues but.) So I got a rebuild kit off an auction site and pulled the trans. I also armed myself with the Ron Sessions book on the TH350. So here's my problems; After reassembling the trans, the book warns about the input shaft locking up when you tighten the front pump. Mine does. I've tore it down 3 times and the direct and forward clutches ARE fully seated, and the input shaft still turns by hand with the trans on it's tail and the front pump in place and the bolts are all started. But as soon as I start to tighten the front pump bolts, it locks up! I also noticed that when I try to push the governor back in, well. It just gets stuck. I tapped LIGHTLY with a small hammer, but it just seems WAY too tight. I really need some help from someone who knows the TH350C quite well.