alright so i plan on getting a z28 when school lets out and i think the first thing i want to do is get a new rear end- it seems like a good place to start before adding other modifications, also its a huge power gain. i was just wondering what all is required to swap out the stock gears to 3.73's and would it be worth the time and money to replace the whole axle/Rear end? also what exactly is meant by 10 bolt 7.5" or 10 bolt 8.5" etc...? is it just what covers the gears and holds the axle together? and im a little confused about trac loc, posi, limited slip differential etc.

Thanks

 

firs off different gears or a different rearend will not give you more hp, it will transfer more torque because of higher rpms per mph. tru track, posi and limited slip are all the same thing just different names and a little difference in how power is delivered to both rear wheels at the same time allowing one side to give when making turns. a locker rearend will lock both back wheels to go the same no matter what. that means when you go around a corner the inside wheel will skid or squeal because it goes a shorter distance than the outside wheel on corners. an open rearend will deliver power to the side with the least traction and on occasion when both sides have the same amount of traction an open center section will deliver power to both wheels. you can have the ring and pinion gears changed to say 3.42 to 1 or 3.73 to 1. meaning the drive shaft turns 3.73 revolutions for each time the tire or axle turns 1 revolution. drive the car for a while, it may be that you will have to spend your money on a have to get thing for it like a opti or plug wires or spark plugs or brakes or stereo,,,, well gota have good tunes.

 

7.5" and 8.5" are ring gear sizes. Generally speaking, the larger the ring gear the more power it can handle. The Z28 rear is a weak 7.5" 10 bolt and can be broken easily by a stock car with no mods (especially a with manual trans because of clutch dumps). The most common rear swaps for 4th gens are Moser or Strange 9" (very expensive) housings or DIY Ford 8.8 (budget, requires torque arm mount) builds.

 

i have read that the weakness is in the housing, if flexes and in time bends far enough to cause bearing failure and gear binding. you can brace it up with a heavier rear cover.