Thanks for the info guys. According to the rules of FSP, I must use the stock A12 engine with only bolt on modifications like a header, carbs, etc. I guess the locked diff would be out of the question then. Exactly how much power would I have to make to justify a locked diff?

I'm thinking at least 160HP probably more like 200HP before you would need that kind of power.
Given you will be seeing maybe 90HP out of a Rebello prepped motor in street prepared I would leave it be.
I've had the H145 LSD on the car for something like 15 years now and it's been trouble free......I've road raced, autocrossed and rallycrossed the car with it. (save the money , you'll be happy in the end). I went 3 years or so without one and managed to do well enough. (On occasion I even managed to beat my friend who's since become National Champ in F125).

Tom

Man, 90 HP out of a street prepared motor? I'm curious to know how that's done without alot higher compression, a cam or serious head work. I'm sure it invloves careful blueprinting and boring the thing and decking the head to the max limit allowed. But even then its hard to imagine 90hp out of a street prepared engine that makes barely 40hp in stock trim.

Got any tips on finding an H145 LSD? It was my impression the things were made of unobtanium.

hey sundat1200 if in fsp I would recomend having the engine preped by Rebello but note very pricey and then add fuel injection with throttle bodies and crankfire ign. the stock rating of the a12 is 68 at the crank 90+ hp at crank is possible. I have a datsun comp header and a 3.90 limited slip rear I may part with also a pair of mukuni's without manifold when I upgrade to FI I am also in san jose Pm your phone # . Note only a few people have been able to get away with running a locked diff and they are more likely to break

I am still looking for a 4.37 gear set for my h145a possible trade for my spare 4.63 gears