Total IRS Costs vs. Live axle?

[natehall37]

Just starting to wonder how much $$ an IRS setup is compared to a live axle? I guess I didn't realize that all of the extras would have to be purchased for the IRS until I started to plan my build. I'm not much of a junk yard searcher either, so I bet I'd use mostly new/reconditioned parts for the IRS, although I'm not opposed to it. Cheers.

[edwardb]

The answer is "It depends" in nearly every aspect. In either case, you can buy ready to use components and pay top dollar. Or you can scrounge for the parts in salvage, and pay to have them prepared. Or you can do some or all of the work yourself. Also it depends on how you're going to use your car and what you expect from it. In some cases, a solid axle may be a better choice. In others, IRS may be a better choice. Another wildcard is the recent release by FFR of the 2015 Mustang IRS setup. I understand you can still order a kit with the older style IRS, but at some point I suspect FFR will cut that off and only accept orders for the new. I'm building a Roadster with the new IRS, so have some experience with it. I have zero experience with the previous version. The 2015 Mustang parts are actually not that hard to find. You only need the center section, knuckles and hubs. Somewhere in the vicinity of $1,200 - $1,300 for basically new parts. The rest of the components come from FFR with the IRS upgrade. By all accounts the new IRS is superior to the old version, and may even be more cost effective, so I would recommend you compare to that one.

[Alig2]

Just finished doing mine, old version, not the 2015 mustang version. $150 for a complete Mark VIII rear clip, $700 for new hubs, bearings, 3.27 gears, and rebuild kits, $80 for a used trac-lock. Did the work myself, so under a thousand plus the kit option price ( which has 1/2 off during recent sale )

[2bking]

I built the old version with all new parts (hubs, pumpkin and cover, knuckles, gears, gear install kit, and Torsen diff) a couple of years ago for about $1900.

[bansheekev]

I also did the older (not the 2015 IRS) for $1650. This was all new parts except the aluminum IRS pumpkin case and the IRS knuckles (both from a 98 Lincoln MKVIII). New parts were differential (Eaton Tru-Track), Ford Racing gears, seals, bearings, aluminum solid mounts, and professional assembly of the rear end. For the IRS knuckles I added new Ford Racing 5 lug hubs, bearings, VPM poly bushings, and had it all cleaned, painted and assembled by Stu Spencer.

You have to add in the cost of the IRS option from FFR over and above the 3 link I guess as well.

Kevin

[natehall37]

OK, sweet. These are exactly what I was looking for. Again, I'm trying to work up a halfway accurate budget. Thanks.