Best axle for a chevy 383 capri?

Phoenixv8 · Post by **Phoenixv8** » Wed Apr 04, 2007 10:48 am

After spending lots of time researching into what transmission to go for I am still none the wiser on what axle to go for

the car is a 1986 Mk 3 Ford Capri

the engine is a supercharged 383 6.3 Chevy v8 pushing out enough torque to mangle anything standard that ford produced for the capri, up to and including a 2.8 lsd and 3.0 axle

Seeing as I want a capri that has some sort of handling in the corners (no laughing back there!) I am doing away with leaf springs in the hope to construct some form of IRS

the jag IRS is too expensive and rarer than rocking horse poo
the 9" ford is a possibility as you can get em with discs fitted
possibly a heavy yank axle ie corvette?

can you guys help?

the plan is run the car through a th400 box with custom gear ratios so the axle is gonna need to take some serious abuse as the capri will be used for drag/strip racing as well as street

Any help will be greatly appreciated

chodjinn · Post by **chodjinn** » Wed Apr 04, 2007 11:20 am

Jag IRS is not expensive at all if ya do it right! I priced one up for my MG at about £1200-1500 depending on quality of parts used, and amount of recon needd. They're also extremely common, most of the kit car (cobra etc) boys used then and there are plenty of people around the uK to get them off, and that offer refurb/modification.

Try Pop Browns or Hauser Racing

IIRC Jay just got quoted £4500 for a for a Ford 9" set up for his monster Porker, while a complete refurb Jag IRS can be had for approx £1700, inc. new shocks/bushings etc.

ian.stewart · Post by **ian.stewart** » Wed Apr 04, 2007 12:58 pm

You want it to handle with a SBC and a blower up front??, it will be a compromise at the best, Go for the 9", there is no real alternative to the 9" in cost , although the 8.8 is now avaiable with all the right bits but expensive, dont bother with the indi rear, the complexiy and expence of trying to get it to work, to get it to work is not just geting the wheels to rise and fall indipently there are all sorts of geometry problems to be sorted, if the suspension you choose, for example has a rear steer built into the geometry, how do you use this, or do you not and how do you design it out, even the jag has its limitations, being very crude in its design is extremly heavy and when you get them narrowed are a pain to get reset in the correct position

kiwicar · Post by **kiwicar** » Wed Apr 04, 2007 12:59 pm

The Jag is the lightest of the three, compared to a ford 9" it is also cheep as chips, there is very little 9" stuff left that is not from the aftermarket any way and you have to import the lot.
The big Chevy would also be a case of self import and aftermarket rebuild, nearly as strong as the 9" but also as heavy as hell and some dodgy geomitry and a transvers leaf spring (post about 86 it is even made of plastic yuck

) and you would have to narrow it even more than the Jag.
I also think the ford 9" is overkill, with a supercharged 383 small block, with a so you will end up throwing away power that you have spent money to make.
the only other things I would look at would be the big BMW and merc diffs, they really are cheep from recyclers but you would bprobably have to build your own suspension set up, not a huge deal and fun to do.
Best of luck
Mike

kiwicar · Post by **kiwicar** » Wed Apr 04, 2007 1:01 pm

er actually what Chodjinn said

ihatesissycars · Post by **ihatesissycars** » Wed Apr 04, 2007 1:09 pm

If you really did want to go IRS (bugger that imo) then also consider the supra or skyline diffs as they appear to be nigh on indestructable.

I know of one character putting over 1200 bhp thru a completely standard late supra diff with zero problems.

ian.stewart · Post by **ian.stewart** » Wed Apr 04, 2007 1:21 pm

I can vouch for the strength of the jap rear ends, BUT it think all Supras are indi rear,

kiwicar · Post by **kiwicar** » Wed Apr 04, 2007 1:42 pm

Hadn't thought of the Japanese stuff but yes the supra does seem to be bomb proof.
A twin wishbone rear, or a twin trailing link plus twin radius arms is not a difficult set up to design (though the latter can be tricky to package in a front engine car), and you can design in enough adjustment to tune it for pretty well all uses. If you have a roll cage built into the car then it should be possable to build the whole set up onto a subframe and mount that onto the roll cage and chassis.
Have fun
Mike

Phoenixv8 · Post by **Phoenixv8** » Thu Apr 05, 2007 9:31 am

Many thanks for all your info guys, certainly food for thought! I had been toying with the idea of a jap setup for the rear for a while (have also considered the supra 5 speed box as they can take a beating and then some)

The car will be fitted with an 8 point roll cage to aid in chassis strength and seeing as I have only just removed the old 2.8i setup I am spoilt for choice really.

Just wanted to get my facts right before heading down a road that I find to be the wrong after lots of hard work and money.
As always your comments and advice are always appreciated

kev_the_mole · Post by **kev_the_mole** » Thu Apr 05, 2007 4:17 pm

Chevy 10-bolt or 12-bolt could be candidates if you want to stay with cart springs.

I have a narrowed 10-bolt with 3.55 ratio posi-traction limited slip diff & heavy duty half shafts in the Healey. The ten bolt is traditionally the poor relation to the 12 bolt but very fast people in the states (see below) use them and the bits can be as cheap as chips due to them not having the 'cachet' of the Ford 9".

There's a good article at http://www.chevyhiperformance.com/techa ... e_install/

which says

How strong is the 8.5-inch 10-bolt? Well, let’s put it this way: Both Dave Henninger and Kurt Urban run these 10-bolts (with spools) in their respective Camaros. Henninger has run as quick as 8.68/151 mph, while Urban’s Camaro runs 9.20s/145. Henninger has never broken a gear and has logged hundreds of runs. That should settle the question of durability.

Nice to see another Chevy on the forum.

Cheers,

Ian