Hey guys, i was wondering if you could help me with a couple issues. Im planning on running a GM ZZ454 crate motor to a th350 with a shift kit in my chevelle, but i ran into a couple problems while disassembling the TH350. My first problem was the shift lever. The transmission was very old, so the shift lever rod was elevated and burred on the inside end. I naively got frustrated after trying a metal file and twister the thing out with pliers.

So now i have a bunch of score marks in the space where the lever rod went. My question is, will it leak? If so, can i fix it?
My next problem is with snap rings. They have been a huge pain in the *** and ive managed to squeeze by until now. The snap ring that holds the sun gear shell to the output shaft is bothering me. Snap ring pliers wont get it out, a hook tool wont, not even a screwdriver. anything else is too big to fit in the confined space. How did anybody that has done this before get by this?

The first picture is of the snap ring area. The second is of the scored area. Also, sorry for the wall of text.