l wanna know how much money getting my monte posi-ed would cost. l also wanna know wat ratio would give me the most power. l believe it has a 3.73 ratio now. Please let me kno all u know bout gear ratios. l know wat they are but dont know wat would be better.. higher or lower numbers.. thanks for all ur help

From Summit you can get a Strange Engineering posi diff for $349.95 plus shipping. But if you shop around you may find a used one cheaper. Just make sure your rearend is still a GM 7.625 in size differential. Alot of people also switch their rearends with Buick Grand National ones.

Check out this to learn how to calculate rear end ratios: http://chevyhiperformance.com/techarticles/148_0208_gear_ratio_calculating/index.html

to be honest i'd leave the 3.73 gear (if that is what it has in it), a posi unit would run about 450 bucks a bearing kit another 125 and to have somebody install it probably another 150-250 bucks depending on their labor rate..if you have never rebuilt a GM rear axel l do not recommend doing it yourself because of the pinion shims, the pinion preload, the diff shims and the backlash all must be within a close tolerance in order to have a long life