Hey guys,

I have a '73 1200 2 door sedan and I was wondering how much horsepower the stock rearend could withstand? Also, anyone know maybe what the gear ratio could be or where to look to get the info? Thanks.

Pretty much all sedans had the H145 with 3.9:1 ratio.

I reckon up to 100kW at the wheels (if driven carefully).

If not driven carefully, then only 70kW at the wheels. Although I know some maniacs who can break them with the standard A12... ~45kW at the wheels.

Chris

Differentials are not rated for torque, not horespower. The H145 could handle a 400hp enigine depending on the torque it put out ...

So, how much torque? No one here has the official specification number. But consider that Nissan didn't use the H145 behind an A15. Instead they went with the bigger H150. Even the A14 B210s used the larger H150 differential.

I'd suggest leaving the stock diff in to start with. What have you got to lose? I've known the A12 to bust the diff also, but then again I've had an A14 for years and it hasn't broken. I've been in burnout comps and had the engine mildly worked and the diff is still holding strong. Just try the original diff to begin with and if it breaks then it breaks. If it does break then you can replace it and incur the cost, but as a cost saver just stay with the original to begin with.

If you can source the 4:11 diff out of a wagon or ute then that might be a good option for you. I know of a mate of mine running a CA18DE on the 4:11 diff and he was fine for ages until he sold it and the guy who bought it wrote it off

I appreciate all of your responses. What I am doing is buying a 13b rotary, (I know, I know, extreme taboo) but I am a poor college student. I plan on running a 75 shot of nitrous. A really cheap way to do it is just do some webbing up with the stock rearend, but I could also back half it and run a four link with a ford 9". My ultimate goal is just to run low 13's, high 12's in the quarter. I think it is pretty realistic, especially if I stay around 1900 pounds. If the stock rearend will handle around 200 h.p. at the wheels I would just do that, but if it ever hooks up, that is what scares me. But, I think it would be fun to try anyway, because a 9" later would not be that hard to put in. Thanks guys.

p.s...

The only problem with trying to run stock datto parts out of donor dattos is that I live right in the middle of the U.S. and there are hardly any old datsuns around here because of winter conditions.

Quote:

then how long is my stok dif gonna last...running demo
s old engine...(worked A15)....hmmm...alot of the time goin 2 hang one...the dif jumps up and down like nuthin else...it scares me...but still hangs a mean skid...

My philosephy is drive till it goes BANG!, then replace it. Untill it does youll have time to find a spare and save up for a stronger one .
I belive that a 9 inch is overkill for a datto even a rotorised one.