NOZ350

Hi all, I have a 383 HK turbo 350 9in 4.56 gears, but I would like to get your suggestions as to what would be the best diff ratio for drag racing and streetability?

I will only be running a 26" slick so revs are a concern with the 4.56, I reckon 7000rpm will pull up the 383.

And street wise, I would like to be able cruise comfortably around town with the odd trip to the coast (wintersun).

Broad question I know but your thoughts would be considered.

Cheers
Noz

pro068

I've got 3.7s, havn't driven it yet with those gears but had them in the Camaro and they were a good all round ratio I thought. Maybe be tempted to go 3.9s??

k383

have 2 centres.......
one for strip.....spooled or somthin
lsd for street or detroit/true trac.

your 383 will have good enough torque to run good numbers
with 3.7's.......

dya dyno your rebuilt engine??

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Karl_HQ

Yep, I agree with K383... 2 sets of gears....

We fitted the Monaro with some mini spooled 4.44's (Salisbury) for some fun... but they are not very practical... OK just driving around town....but, revving its nut off driving on the open road... The acceleration difference from a 2.6 to 4.44 was awesome, but I cooked the speedo... and I think I'd better fit a shift light or maybe a limiter before I blow the old girl up....

Streetability.... 3.55 or similar I rekon would be the go....

BossHoggett

Depends what your willing to put up with with streetability.
if your running 4.56's at the drags on 26' tires im guessing your pulling close to 8000 odd grand out of her. Then coupled with a power band at best of 2500 rpm leaves maximum torque around 5500 so then as a successful convertor speed 5500 Under about 4000 the engine will become boggy and torque will start to fall to hopeless. and you'll be trashed by people on push bikes at the lights. your convertor stall speeds will wreak havoc over or time with your bands/clutches... and like most guys will revert to driving your wifes hyandai for the driveabity and fuel consumption. In my opinion the difference between a street car and a race car aren't blurred they're completely different machines.

NOZ350

True but everyone wants the best of both worlds hence my question

azzahstylez

i got 3.9 on the SS and driving around town and on the freeway is easy as. doesnt rev its ass off but made a big differance to the standard diff. when i was in the market i was tossing up for 4.11 or 3.9 and yeh i went with 3.9s

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BossHoggett

try a 3 speed box with a 1:1 ratio, then see what you think

allports

Um Boss it is a T' hydro 350 3 speed.
IMO I'd go a 4.11 the 4.56 & 26" tyre will be doing about 7050 (no slippage) @ 120 mph.
A 4.11 will be turning 6400 (no slippage) at the same speed. Everything is relative though. Depends what mph you can run.
I think you'll find PRO68 gave you some good advice there with a 3.7

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allports

as did k383

__________________
If you plant a cucumber, you get a cucumber!
Two things are infinate,the universe & human stupidity, and Im not sure about the universe.
Albert Einstein
Without deviation from the norm, progress is not possible. Frank Zappa

BossHoggett

refering to azza

mrprem

Yeah I reckon between 3.7 and 4.11, no lower than that. My car only runs two tenths quicker on slicks with 4.11's than it does with Radial T/A's and 3.7's so not really worth the drivability issues I think... Revs on the highway with 4.11's are an issue, not that 3.7's are great but they're definately a better compromise.

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NOZ350

I reckon it should be good for 120mph (or I hope) I was oroganally heading for 4.11 but I am starting to lean towards 3.9's I think the 3.7 may lower the revs to much over the 1/4 mile.

But I am still interested to hear your thoughts, especially if you have a 383 HK

Oldman

110Kph with 3.7 & 1.1 ratio gives around 3300-3400RPM so depending on stall as to how much slip you get on the highway.Then how far you cruise as to how much extra heat you build up.With 3.7s I cross the line at 5700 roughly @ 102mph with 232RWHP.I have a 3800 stall & traveling 70ks to & from strip don't have a problem with it.Now i'll have to travel 600ks i'm building a trailer as i think this sort of distance could cause a problem.