Outer Limits 4x4 Board

wonder how many hp or torque can a 75 series 5spd take before it constantly breaks? as i have a 308 in the car and want to do it up to around the 400hp mark.

cheers

I had the head flowed and a lumpy cam put in, approx 120kW at the rear wheels on 35in tyres. 0-100km around 8sec or so if that gives you more of an idea.

I haven't broken anything yet although my understanding is that 5th is the weak link in that box and with the 35's I'm spendng a lot of time in 4th. Off road I guess a lot comes down to how you drive. I'm sure if I revved the old 3F high enough and dumped the clutch I could have broken something!!!

well once i get crawler gears i spose i will be driving it very gently but noy i rev the shit out of it offroad cos it has no flex.

just want more power so i can get along the road better will be running 33's on street.

the motor has a mild cam and the valve tiiming is changed a bit so it's got more go than a standard 308 black

as long as ya dont go dumping the clutch at 8000rpm lol
it should hold up for now. But the question is for how long

known 2 wrote:wonder how many hp or torque can a 75 series 5spd take before it constantly breaks? as i have a 308 in the car and want to do it up to around the 400hp mark.

cheers

If your talking 400 HP out of a 308 it will be no good off road as it would have less low down torque than a Camira engine and absoloutly hopeless offroad how much do you think you need to spend to get 400 HP easy 10k+ and if you had 400 hp you would be strugling to keep it on a track. As for the gear box strenght it will handle what ever the 308 will put out, had a mud racer years ago with a 380 small block Chev 498 HP on the dyno ( cost over 20 K ) 10 years ago and had a 75 box/transfer and never had a prob. Have mates in the comp scene with goods 350's and never had a prob and a mate with a 454BB in his everyday 75 and it keeps going no probs. The only box to keep away from is the HZJ75 as the gears and shafts are crap and s**t them selves all the time. Any one from a 60, 70 or 75 with the with the 2F, 3F, 2H, 12HT, 3B or 13BT engine are all good keeping in mind that the 4cyl Diesels have a longer input shaft.

Wally

Unless you have efi I would not even bother with trying to get 400hp out of a 308. There ticking time bombs.

Take it from someone who has spent big dollars on 253 / 308 carbie engines, its just not worth the coin spent.

Just buy a 400 small block. You can get about 350 to 450 Hp easy with sh*t loads of torque ( which is what you need offroad ) and there reliable.

For what you will need to spend on the 308 you could drop 400 and t 700 auto in and have enough money left to put 38's on it.

Dont get me wrong its just my opinion but i wasted alot of money chasing Hp in 5L.

Nick

I dont think he asked how to get the power and what problems the motor will have. Just gear box strength.

thats all usefull info thanks. i just wana get a bit more out of it for now cos it's allready there rather than buying another conversion kit.

thinking of maybe putting a stroker kit throo it to get more torque cos i like the 308 drives nicer than a 350 chev