Whats the diff?

[HG383PREM]

I've got a nine inch in the prem, it currently runs a 2.75 LSD centre. I am looking to change the ratio in it. It was great while the car was set up as a cruiser with the mild 350. As the 383 is quite a bit grumpier, I want a ratio more suited to the motor.

Everything in the motor is set to come alive at about 3000rpm and go to about 7000rpm. Its good for about 420ishHP at the fly when I sort the other bugs in it.

Theres a 3000 dominator histall and a shift kitted T400 in the mix as well.

I thought about going 3.5 to 3.8, somewhere around there as I would like to have a crack at the strip because I have never done it before.

Is it worth going 4.11s or will that be a pain for the cruise factor.

Has anyone had any dealings with good diff people down here in Tas or is it a case of getting stuff in from the mainland.

[NO.TOY]

hey mate i had similar setup in my hj ute i had 3.9's in it and could drive it from syd to canberra no worries but still work well on the strip you've got to have a happy medium.

[HG383PREM]

Yeah, thats what i'm chasing "the happy medium". We love getting out in it and cruisin around, lotsa nice roads down here.

Can anyone recommend a good diff place for bits?

[noslx]

hey shane let me know what your after i know a few people who do diffs

[HG383PREM]

Cheers Andrew, its still a little way off yet as you know where its up too at the moment

I've got the diff in bits now and know what I need, I'm trying to let the wallet get fatter before I tackle it but its just not happening yet

[DaN VH]

Shes gonna be a real monster with a new diff mate, hope ya got a few spare changes of undies :) I reckon you should go for 3.9s, i think 4.11s would be too much for the street with your donk shed be revving her **** off. 3.9s would be a good balance of cruiseyness and sillyness.

[HG383PREM]

Gday Dave, hows it goin?

I'll just wear my religious undies mate, i'll be able to get a few miles outta them

I've had a quick yack with the bearded one, he reckons 4.11s "are the biz" for the engine

I've had a sticky at a program that factored tyre diameter, ratios, engine specs and all that crap into the equation & i'm leaning that way as well.

Worst case senario, i'll do another centre with a more street friendly ratio, doesnt take long to swap a centre over

[DaN VH]

Going bloody good Shaneo! Mate if the bearded one says 4.11s, go the 4.11s :) I like the street friendly centre idea too, why the hell not! Plus how often are you gonna be taking it down the drags! Probably a fair bit ay haha.

Hope you and the crew are doing well mate!

[KINGHZ]

gday mate, thought I'd add my 2 cents worth!

I run a similar set-up to you with a 9 inch and shift-kitted T400, although I'm running 3.55 diff gears and a 4500 stall-converter. It's a pretty tight stally so I can sit comfortably on 100kmh at just under 3000rpm, yet i was still able to run a 12.8 down the strip (my 5L runs similar power to your 383)

i'm pretty happy with the 3.55's, but i think because i run a higher stall-converter it's compensating a little for gearing. with a lower stall i think you could benefit from 3.8 or 3.9 gearing.

i'd say the 4.11's would be good for the strip but would make cruising a bit of a pain, so I guess it just comes down to which activity you plan to spend more time doing? i'm thinking 3.5's would sacrifice some of your acceleration, and 4.11s would sacrifice cruisability, maybe 3.8's or 3.9's would be a happy medium??

anyway i hope i was able to help in some way, good luck with whatever ratio you decide to run!

[NO.TOY]

and in answer to your question wats the diff? its all a matter of a pinion.