SPOautos

Hey guys, I have a friend with a 79 and need to know roughly how much power the rear end can handle??? If it cant handle much what would be the best thing to replace it with?

I know it will have to be replaced with something strong pretty soon as its going to have over 400rwhp pretty soon but I'm wondering if the stocker could at least live thru some dyno tuning???

Thanks,
STEPHEN

mperformance

I was comparing the two shafts, ones from my 79 and the ones from my 85...the 79's are crap!

SPOautos

So anyone know what a good replacement would be? I'm looking for something that will hold 500rwhp without breaking. It'll be taking drag racing abuse but also be driven on the street so it cant be for all out racing

Thanks,
STEPHEN

Directfreak

iTrader: (2)

Look up AJC13B and ask him and Aussie friends. They did several different rigs to hold that much power. Another 7's rear end will not hold that much power or bolt up if it is from a newer car.

Around here, lots of people use Ford Rear ends, or Datsun P/U truck rear ends.

Check Granny's speed shop online. I believe they have a bolt in Chevy rear end to hold the power of the V8 conversions.

Let us know what works out.

Winnipeg85GSL

If you're gonna change it, go Ford 9 inch. Bulletproof.

MIKE-P-28

iTrader: (1)

And if not, PLENTY of them available

Pedestrian X

you read ym mind, i do ahte fords but ill admit the 9 incher is the way to go

peejay

There were two axle shaft sizes, '79-83 and '84-85. The '84-85 axles are bigger, however the housings are weaker. Some feel that the weaker housing will deflect more under load and cause the axles to flex and fail more often than the earlier ones.

As a practical matter, it's amazing how much abuse the little Mazda 7" rear will take. Just don't do one wheel burnouts, that WILL cause you to blow the diff. (Ask me how I know )

Blitz0309

Peejay... How do you know?!?!?!

Keaponlaffen

Yeah, enlighten us with your rotary wisdom peejay

Jeff

Adsy01

I both agree and disagree to this but, here in the land downunder the "improved production" racing guys are stuck with the 1st gen rear end.. most go with the series 3 (84-85) rear end.
some brace it to give less flex but this is also done when the housings are bent for negaitive camber on the rear end. (circut race cars were talking here)

Optional rear ends over here,
ford 9"
toyota hilux (4x4)
GM borg warner

RotaryNotary

Newbie here, had it only about 2 months....

When you say "one wheel burnouts", what do you mean? I assume hitting the gas hard around a corner is fairly safe, or am I doing damage that I don't anticipate?

SilverRocket

Naw, that's ok, that's what 7's were made for I think he means spinning the living hell out of one wheel by means of a stationary burnout.

diabolical1

iTrader: (3)

yeah ... i think he means not to do crazy-azz burnouts with the open-diff rears ...

on that note, just out of curiosity ... does anyone know how one would go about increasing the lockup on a stock Mazda posi rear ... i mean, short of 100% lockup by welding ... i'm thinking something more streetable.

twister

As adsy said, I run an Ip car in OZ with floating hubs from Guru Racing. They supply billet steel axles, Torsen Centres and the actual hub that bolts directly onto your existing rearend. a sh__ hot set-up, real strong. Then of course your weakest point becomes the actual diff gearset.