Kirkham Differential

[lineslinger]

I would be interested in hearing the opinions of those Kirkham owners who opted for the Kirkham differential and from those who went an alternative route and installed something of their own choosing.
I am curious as to the performance and reliability of the Kirkham as opposed to an alternative. Maybe someone could elaborate on any costs/savings realized as well as well as any problems incurred by choosing a different rear end.
Thanks for the help.

[saltytri]

After about 3000 miles of street driving, I haven't had a lick of trouble with my Kirkham diff.

[lineslinger]

Saltytri,
What kind of HP are you putting to the asphalt and your rear end ratio?

[Igofastr]

1000 miles of smiles on my kmp diff. No problems at all. 511 bph, 560+ lbs torque.

[cobra101]

I have used several, never a problem. I believe the actual tooling and majority of castings actually came from McClusky and ''it dont get no better than Mike McClusky''

[rsimoes]

I was at Kirkham's last week and we talked about it. They have seen it perform perfect with more than 700 ft lbs through them. . .

[4pipes]

Mine leaked due to a porous casting. It had evidence of peening to seal it, but it wasn't effective. It would weep fluid all over the gas tank. My builder had a different source for a housing and he built a whole new differential using my original internals. Doesn't leak at all now.

[lineslinger]

Its beginning to sound like when all factors are considered the Kirkham rear diff. option is worth the substantial cost.
4pipes, did you approach the Kirkhams with your problem and if so what kind of response did you get?

[ENTDOC]

I would use a Jag diff. you should be able to find one and rebuild it for 4-5oo bucks. I see no real advantage to the aluminum 5000 dollar diff. It is nice but too pricy. I have the aluminum by the way

[cobra101]

Why would someone recognizing a leaky casting resort to ''peening'' rather than repairing by welding or throwing the defective part away and providing a ''non defective '' part?

[saltytri]

lineslinger:

I've haven't had it on a rear wheel dyno but the motor did 456HP and 421 lb/ft at the flywheel. Ratio is 3.46 with a TKO600.

[lineslinger]

I am assuming the shot peening was an attempt to condense or compress the skin of the housing and seal it, some kind of method to try and eliminate the porosity problem and maybe stop the leak?

[Lew Ledyard]

I have about 2500-3000 miles on mine. Not a drop of leakage. Everything seems fine. 630+ hp/tq.

[Rick Parker]

Could powder coating internally or painting the interior with glyptal eliminated the seepage?? What Say You All?

[lineslinger]

I'll bet it would Rick, as long as the hot tranny fluid didn't have some strange additive that would break down the paint.......20 days to Chile.

[Power Surge]

From what I recall, the KMP rear is a replica of the original Salsbury rear, just with an aluminum case. There was a thread in the Kirkham forum about using a Jag rear instead, and if I recall, that requires modifications to the car to make it work.

[jpfletch1]

Mine has performed well with no problems. I am running 632 hp/ 625 ft pds torque. I think the Kirkhams really try hard to bring every one a good product.

[ENTDOC]

the jag diff will fit easily with the proper mounts supplied by Kirkham

[kris-kincaid]

If you get a used Jag diff for say $500, then get ENTDOC's source for rebuilding them at $400-$500, then buy Kirkhams $375 adaptor to mount it, you're at $1375 or so. Does Kirkham include the drive flanges to hook up Cobra half-shafts to the Jag diff in the $375? If not, add that on.

In the end you're saving $3500 or so on a $70,000+ car. Nice!

[ENTDOC]

agreed! 3500 = monster heads and toploader,clutch