Chevrolet th350 auto transmission changes gear late..?

I have a pick up truck running a chevy engine and box- the engine is the old (poss 80's) V8 diesel 6.2 (i think) with a vacum pump where a distributor wouild be on the petrol engine-this pump is connected to the auto box via rubber hose and makes the gears change-3 speed- however it changes gear late--question- is there any way to make it change gear earlier.?
Chevrolet th350 auto transmission changes gear late..?
It is called a shift plate, rather easy to modify or install.
Chevrolet th350 auto transmission changes gear late..?
shift kit street or strip th350 $39 www.summit racing.com

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