ok i have a basic 350 my guess is around 350 horse my car has the 9 bolt witch i have heard nothing but good things about i want to put 4:10s in but i was wondering if i should spend money on this rearend or look for a 10 or 12 bolt any input will be appreciated

 

The 9 bolt should be able to handle that. What gear ratio do you have in it now? If it's a 2.77 then you will need a 3 series differential too.

 

i acctualy have not pulled the cover off yet to see becuse the tag is missing but im sure it a verry high ratio

 

You don't need to pull the cover off to determine the ratio.

Just rotate the axle & watch the pinion. Count the # of times of the 2 & you'll get very close to the ratio. Close enough to be abe to determine what it is.