Stock differential with a s14

[ASHTC510]

I have a 71 510 with a S14 in it .I was looking to know if I could stay with the stock rear from the 510 or I need to upgrade on size and ratio.I have a opportunity to buy a r180 3.9 from a 88 200sx.

[RMS]

depends on tire and driver but having a spare is a good idea.

[Three B's Racing]

I also have the SR20DE S14 in my 510 with an STI R180 3.90. Do it, get that pumpkin because a one legger with 165 stock HP doesn't hook up well. If it isn't CLSD I wouldn't bother as you current ratio is likely a 3.90. Work on getting a limited slip.

[demo243]

As said above ^^^ depends on the driver...

If you plan on dumping the clutch and doing burnouts all the time your probably gonna run into trouble....

But Subaru has been running R160s in cars with 150-200+ hp for a while including on their turbo models - Forester XT, Legacy GT, WRX - and guys are running those at 300+ hp.

Its the half shafts that are likely to give you more trouble before the diff.

A clutch limited slip center unit will definitely help prolong the life and give you better performance... although they are getting tougher to find.