10.5 gearing running gm 120?

[cartz1984]

now that these speedo,s advance im lost with the gearing. whats the best way to check your some where close with the gearing is the a overall ratio to get close to or does it depend on the track ect? i run a nosram cooling fan/haetsink on the motor and its running well but still getting hot? i seem to be the only one having to run a fan as otheres are running simular set ups without??? any ideas or tips i would appreciate as i dont want to go the wrong way with the gearing and cook it!