Can somebody fill me in on the characteristics of a tranny with a shift kit that would let me know without question if my tranny has one installed or not? Is the only sure fire way to remove the valve body and inspect?

 

Depending on the kit, they usually boost pressure over stock. You could put gauges on it and check your pressure. Just driving you probably wouldn't know. My truck shifted firmer into OD with the kit, but I only knew that because I knew how it shifted before the kit.

 

Does a stock tranny have full gear selectability at speed? I'm able to select my low gears and it will downshift.

 

most modified vb allow flow in park, easy test check tranny fluid level in park, then recheck in neutral, the level will be the same, if there is a difference in fluid levels, it would be a stock VB