Various issues with 1986 Sierra P/U

[fang508]

So I have a few questions regarding some issues I have fixing up this old truck. There is this metal bar/bracket that sits right next to the starter. It seems like a tension bar because it can bend easily then back again. I had to have another person pry on it with a long bar so I could drop the starter. Can I leave the bracket off without problems?

How loose should a transmission be without the engine attached? I am putting a crate engine and new headers in. While I was taking the old beat up rusty manifolds off I noticed I could rock the transmission any direction by a few inches.

What is the difference between sbc and bbc clamshell mounts? I bought new sbc motor mounts for my crate engine and the 7/16 x 5" center pins I wanted to reuse had so much side to side play. So I bought 2 1/2" x 5" bolts and it fits nice and snug. Every forum I search for sbc center bolt sizes says I need 7/16" yet 1/2" fits so much better? Seems kinda odd I am running into these problems.

Thanks