340 not running anymore...Help Please?

Airplane gears? I googled and found this airplane dog, but no airplane gears.....

Hehe.... but, seriously..... I can order the spring kit. It seems like a good idea since I don't have much faith in the way the past owners set this car up. I would like to know more about the different gears you are talking about so I can make an educated decision on my spring selection. Thanks