RearEnd
 

Im about to upgrade the stock 2001 gt rearend to a 4.10..Do i need to upgrade my stock splines to 31s or will i be ok with 28s with over 400 hp? IM NOT SURE.. ....Plus do i need to try to rebuild my differential or buy a complete one from AM....im over 30,000 sooo ill haft to replace berrings ,but Am doesnt offer any kits except for the motive..but im thinking Ford racing..any ideas.....

If you have the extra coin, now would be a great time to uprade axles and diff. You could either go the 31 spline route, or get stronger 28's. If you go with 31's you will need a new diff.

um,,
 

Am i right stock rearend is a 8.8 right?

If you have a V8, it's a 8.8", otherwise, 7.5." As gotMach said, if you got the cash, upgrade since you'll be in there anyway. Otherwise, stock will be fine unless you drag w/ slicks.

Axles
 

Yeah its a v8,I will eventually be going with a 10.5 rear tire and im right around 400hp, In the distant future i hope to go with a crate motor with a forged bottom end,so i guess ill need the rear to be beefy .I see that AMs axles dont come with bearings do i need bearings? If soo why dont they sell them or atleast tell me? ..Also i noticed that they have a differental thats comes with carbon discs thats cheaper then one that doesnt, whats the diffrence? And that the motive gear is the most expensive followed by ford racing and richmond, any ideas on which is better?..For a project that ive seen qouted as a $400 install i think it just went up with the addition of new axles, new differental, new gear and install..OUCH..Any advice guys?

Axle bearings?
 

Do i need axle bearings? if i replace the axles? On AM they say on the 31 spines has hardend bearing seats is that bearings built in to axle? Um im not sure?