Like Title says I need help figure something out. I don't know what rear I should run. I am building a motor that will produce 400hp to the wheels without spray. I am running a t5 trans.

 

depends on how much you want to spend and how hard you are going to beat on it....if price is no object 9 inch ford

 

Money is a little tight but not too much.. I am going to get ever horse out of it, I really dont want to run a 9inch tho

 

the t5 will not like that kind of power, and will make it known to you shortly thereafter

 

what manual trans you think i should use than. I don't want auto

 

The T5 will blow up before the factory 10 bolt will. If you want to stay with a manual transmission, upgrade to a T56.

You have very few options for a differential. Live with the factory 10 bolt. Even doing a few of the beef up modifications still leaves the diff with a tiny ring and pinion.

Find a factory 9 bolt. It's stronger than the 10 bolt but parts are just about non existent unless you want to order something from Australia.

Find a third gen Dana 44. It was offered in the SLP Firehawk and was available over the counter from GM years ago. It's the strongest production diff available but are now very hard to find. If you do find one in good condition, it can cost about the same as an aftermarket diff.

That only leaves you with 2 other options. An aftermarket bolt in 9" or 12 bolt. Unfortunately either one will set you back at least $2500. It's the price you need to pay if you make lots of power. A high powered car is not just about the engine. The rest of the driveline and chassis need to be upgraded as well to handle all that power.

There's also a beast of a differential offered by Strange. It's a third gen bolt in Dana 60. Even my car doesn't need such a monster of a diff.

I'd say run you you currently have. When it breaks, then decide how much it's worth to repair or upgrade.