Mechanic questions

[BGarza13x]

So, I tried to take my truck to a mechanic to do simple things, oil change, tune up, change master cylinder... things I just haven't had the time to do recently, but mainly to diagnose an issue with the steering that is too loose. I intended to pay like $300-400 for the little things and any other things they found.

They are now telling me I need a new starter and flywheel, and that I needed a new steering shaft and that one of my freeze plugs was leaking. Grand total $1600, not to include any of the other small things or anything else. I'm not fixing to pay that much (nor am I able to).

So, I am trying to buy parts to do the work myself. When I search, it lists 2 different flywheels, a 168 tooth and 153 tooth, how do I know which one, without having the truck back in my possession? Also, would I need a whole new steering column? They just told me that the shaft, going into the steering box, was worn out and needed replacement. On the invoice quote, it just says "steering shaft".

I have a 69 C20, 3/4 ton. I believe it is a TH400 transmission, 350 engine.