1970 C10, 4x4, 4 speed overheating/ clutch adjustment

[Double Stack]

How’s it goin guys? I just picked up this 1970 C10 in pieces, and am lookin for a little- hell a lot of help. I went to retard the timing because it was dieseling when I would shut it off even when cold. The problem is the timing mark doesn’t look like it’s in the right spot or somethin. I gave up on the timing light, and decided to do it by ear. I got it to stop dieseling when cold, but now it’s over heating. The timing mark is about an inch or more before the tape/ readings on the crank/ pulley. So running at it’s best it’s not even within the measurement marks. Is my distributor in backwards? I’ve been reading and reading, and have found that timing, and clutch adjustment have direct effects on engin temp. As well as radiator size, and I’m pretty sure I’ve have the origanel radiator. Also, it looks as if the thermostat is open because the upper radiator hose is hot, but I can’t ever see it come into effect with the temp sensor. I don’t know how to adjust a clutch’s free travel, but I’ve been watching youtube videos so I’m going to give it a shot in a little bit. Actually, this is my first time trying to do the timing too, but I’ve watched a couple videos and read the instructions that came with the light.

O and I wanted to add that I read about air pockets in the coolant systems of new engines, so I tried leaving the radiator cap off and bringing the temp up to 215 to 220, but it never blew the air out so I shut her down. Does this actually work? Is there a better method?

The truck doesn’t like going into first or second, and kinda grinds when going into first sometimes. The transmission was recently rebuilt and a ten inch clutch was dropped in too.

Here’s a couple pictures or the truck how I got here, and now that she's back to gether with new wheels, tires, and windshild. I can take more if it helps out. I was thinkin about taking some video with the timing light going so I could show how off it is. She has the 1969, 350 4 bolt main.

Any ideas!?!