I have the aluminum diff behind a KC 482 motor, and it is fine...only problem I've had was with venting it properly. Make sure you get an original style cover that has a vent built in to it.

HRJ

And it's not even that much savings. You still need to buy the axles and it has to all be installed in the car. The Kirkham's 5k rear end option gives you the entire rear assembly, installed and set up in the car. Plus it's an alloy housing, with all NEW parts.

So in reality, if you factor in using a used cast housing, used gears, and a used diff, as opposed to an alloy case, all new parts, factory installed in the car, what are you really saving?

Interesting comparisons.................

If anyone is interested I have the parts to make Ford nine inch IRS for original's, shelby's, kirkham's or any car that uses the original parts. Complete rearend your choice of gears would be around $3000.00. This would include everything to the yokes for the half shafts. There are alot of benifits to this set up hp/torque, cost, speed to change raitos (about an hour with a spare third member) and part are very available new and used depending on the budget. For $5000.00 you could have the housing and 3 third members with different ratios. If anyone is interested drop me a line at mknos@att.net or call @ 602-400-7725

Thanks,

Mike

alternate rear
 

lineslinger i have a rear complete from accurate machine products half the price and just as nice george petrus from torrance ca it been holding up to 612 hp keith craft and loving it

To those of you who went a direction other than the Kirkham, how big a deal was or is the retro fit, anyone do any fabrication and or welding on the frame? How extensive was the "alternative" component modifications....milling, cutting, grinding, welding.... I can handle these but to what length does one have to take, say.....the Jag rear end.
Or, do the alternatives you fellas speak of fall into the "drop it in" category, with some minor changes.
I do have some concerns about a retrofit that looks way out of place but I am really getting tight on the budget and you know who is right there with me.
Mark

the Jag will fit just as the aluminum will ,both need the mounts as supplied by Kirkham. By the way Kirkham charges 750 bucks for the halfshafts. If you cannot find a good Posi jag diff and buy halfshafts and mounts for less than 2 grand ,then you are not trying. Most of the early cars had jag diffs and the only reason Kirkham stopped selling them was because they are getting more scarce. There is nothing unique about the guts of the aluminum diff ,it is off the shelf stuff. Unlike power surge,I think you are saving a lot. As I stated,I have the expensive set up and I tell everyone to get the Jag unit and spend the money where it can count more.

Well, I'm entitled to my opinion just as you or anyone else is. He asked for people's views and I gave mine. I do understand your point on saving some dough. And if he already has his car, then going with the used stuff might be the way to go. If he didn't have the car yet, then at least you get the stuff installed for the price from Kirkham.

I do not recall stating your opinion was not entitled; in fact, what opinion could you give other than your own?

I truly appreciate the input from all you guys,
I was looking for information in making a budget/build decision and I am getting quality info. None of the feedback is wrong......just different, and thats what will help me figure this out. Differing opinions keep you thinking and offer options I would not have considered.
I/we have the engine finished and my son and I are going to try and get the next step of this project started before he starts college next fall, we did the motor together and now on to the next step together. If he would have gone to a state school instead of getting accepted to university in DC (sorry, had to brag him up a little) things might be a little looser in the dollar dept.
A big part of this whole build is letting him learn how this all comes together and understanding the intricacies of an automobile...like how a rear axle works
Please keep the feedback coming, every little bit helps.

lineslinger, this is a good option:

I thought so too Kris, a nine inch IRS is an attractive option, now to check out each of the alternatives offered.

Question for Mike and Kris,

Does the 9 inch Ford solution also fit a Kirkham 289 or original AC 289 leaf spring car?
I think I have seen this setup in a High Tech.

Clearances are very tight on a leaf spring car.

Thanks

Bert Brown

Yes, the nine inch will fit in a 289. The vent must be move from the top to the back to prevent interference with the upper sheet metal on the rear tower. I always set them up with a vent bung on both top and back and just plug the one you don't use. As for install it is a direct bolt in no cutting or welding, if the frame is to original specs. You are correct on gear changes drop the drive and half shafts, pull four bolt on the houseing and drop it out. Then it is just like changing a nine inch third member and reinstall the housing. If If I remeber correctly we were doing it in under an hour. Also if I am not mistaken to change gear in a salisbury, if you went above or below 4.11 you had to change the carrier also $$$$. As for George he is a great guy and one I have known for years. I don't want to get in a bidding war but I have parts for about 20 of these rearends and I only have two Cobras so I will make sure I am competive on any apples to apples set up for these parts. The price I quoted was for a complete housing, Third member (NEW PARTS) your choice of ratio w/locker, stub axles, bearing/seals, and hub yokes. If this becomes an option which people are interested in we can also go back into production on these with no problems.

I will post a photo in the mourning as well as e-mail them to all those who sent PM.

Thanks for all the interest everyone,

Mike
NOSMS

KMP184 has a Jag rearend...purchased and installed directly at Provo years ago. Nothing against the arruminum one, but I preferred to throw the money into things that truly matter like the Shelby block, Velasco crank, etc. in the motor. The internals are the same for the rears anyway. Paying for the arruminum rear seemed about as dumb (to me) as paying $20-30k for a few phuking badges on a replica.

When you're actually the one paying...the money spent on such items is important for the final budget. I'm certainly not a penny pincher when it comes to this car...nor can anyone ever accuse me of babying it. I don't crawl under the damn thing to look at the differential ever damn day, so it seemed like money would be better spent elsewhere.

If you're going to run the arruminum thing, might I suggest you polish it and replace the removable access panel in the trunk with plexiglass so you can comb your hair in the reflection...presuming you have hair. :p

Weight savings? Seems to me when a fat ass is sitting over it, a few pounds ain't gonna matter...besides, it's at the phuking rear of the car.

The 9" IRS sounds promising...great concept. Hope it works out.

To insure that those who get overly defensive when someone disagrees with them don't start whining...the arruminum rearend is a nice piece and folks who have them should be proud of their choice. However...it is not the only alternative by any means.

Yes...this is just my opinion, and others are entitled to theirs regardless of how assinine they are.

:cool:

My car is actually signed by him! (Jamo).:D

I am so proud.

Jamo,
Stop holding back and tell us how you really feel..... ;)

I've seen the aluminum rears and they are very nice, but what is the advantage? You can't see them, they have the same internals, and as far as weight savings, what does 20-30 lbs really help in these cars?

The 9" Ford sounds interesting on the surface until you realize in a 2200-2400 lb car, how many people have really had any problems with the Salisbury or Jag rears? When it comes down to cost/benefit, IMHO, the money can be better spent on quality items elsewhere.

Bob

After ready this thread, you would think we are talking about Denise Rischards" rear end (very fine one I might add). The thrust and vitality makes me proud.

If I find a Kirkham with the alum. rearend fine- if I order I will use the jag I have had in the shop for ten years. I think the 9-in is a waste. Buy the time you pull it out and swap the center section it would be faster and easier with no mess to have an extra jag to swap in. Not only that it would look like a less expensive kit car from the bottom.

Jamo, The Velasco crank is waaaayy overkill for anything making less than 800hp, and I'm not sure how a $5200 Shelby block is better than a $3500 iron Genesis or an original block. I guess it all depends on who's writing the check, eh? :cool:

Just to be fair, I didn't buy an aluminum diff either, I got an IRS 9".

Assactly my point, my friend...folks have many reasonable alternatives in how they spend their "$70,000." :)