Sat+now Seized Engine, Advice

Yea I put the engine in a long while back. It is a manual now. It was difficult to turn from the beginning but I didn't remove the plugs and belt to see if it helped. It wasn't that difficult just more so than what I would expect. It always started so I guess that means it couldn't have been that difficult.
There aren't any ridges just some gunk from what I sprayed and probably the carbon with it that fell into the engine from the carb cleaner.
Well I can't tell much without removing the tranny which, new engine or not, I will have to do anyway. Aside from cleaning everything and trying to get it to move better this is my next step...

If it needs an engine I don't know, I'll probably have to sell it because my time is running out.

Thanks guys

Also when I drove it the tranny doesn't want to stay in second gear. I don't know if it's the tranny or the used pro 5.0 short shifter needing adjustment.

So I rotated clockwise a bit more, cleaned up the walls a bit more but there wasn't anything to clean really, they look normal. I finished pulling the tranny. I did not remove the flywheel or clutch or bell-housing.
I tried to rotate some more but it's locked up again.
At this point I'll pull the engine.
My only question is will it be something fixable without a full rebuild, if not I'll be choosing one of these used engines.off CL.
I'll have to pull it apart and inspect.
Any bets? lol

that would be nice. I wont be able to pull it till Monday so we'll see.

Update: Sorry it took so long but today I got some results.
So long story short, I had to get a new piston for the Hoist, $65 at HF. The weld for the spine of the hoist then broke with the engine barely raised, thankfully, $40 at the steel shop. got it out+began tear down.
Took oil pan off and used a feeler gauge to check the rods and was within spec, about .0015, .0020 on the rear pair.
I had not taken the crank pulley off yet, I decided to try and get the pistons out.
I began at the rear and worked my way forward.
I was ably to get the crank to move about a quarter rotation backwards and clockwise, but it took a lot of force.
At no point did it break free. Finally I was at the last piston, drivers side front of engine. It was particularly difficult to get out, but nothing crazy. It appeared to be a lot of rust as I removed it and what do you know the crank began turning, like butter. The cylinder had some rust but nothing crazy and some steel wool and phosphoric acid gel took it right off.
It cleaned up nice, need to give it a good hone, It may have been more carbon seizing it up, there's still some stuck to the wall, I didn't mess with it much yet.
So at this point it looks like everything can be reused, I may as well replace all the bearings and whatnot. I am going to look into some cleaning process that a speed shop may offer. Gonna look into that now. Maybe I should make a new post to ask a few questions on that issue. I saw summit had a kit fairly cheap.
Apparently the project sat so long even the tools began to fail ><
Murphy's Law
Yea it's filthy but all that stuff seems to be washable, messing with it tomorrow.
Thats carbon on the wall, not rust.

yea I think youre right, not sure if a hone will be enough ><. Here's hoping.