Finally! A solution!! What we have here is the ultimate short wheelbase 911 rear caliper solution. This kit is the cleanest, the easiest and by far, the least expensive way to get a real caliper on the back of your beautifully elegant SWB (1965-68) 911.
We field these questions daily...
* Will other calipers fit? There are a few ATE calipers that will bolt on to your odd 2.25" spacing (various Alfa and BMW makes) but again, the piston sizes can be either too small, just right or too big (as in 42mm for the 3.0 CSI rear calipers) and, again, you're stuck with the smaller D30 pads. You'll get a little more rear bias (which can be dangerous in the case of the 42mm pistons) but, no benefit of more friction material. No real benefit here.
* What about adapters? - We looked at various adapter styles and, none of them really made us feel safe and comfortable in a track situation. None of them really exist right now regardless.
* Can't I just change the mounting ear spacing on the rear control arm? - Yes, you're welding cast iron/steel. Make sure you know exactly what you are doing regarding welding cast metals. The item needs to be heated to 800º, welded with perfect penetration and then cooled properly. Probably not a great idea for a control arm on a really cool vintage Porsche and, not something I'd want to sink my confidence into at the track.
* Can't I just change the mounting ear spacing on the calipers? - Yes, read above regarding welding cast steel/iron. In fact, this project started out with the thought of designing "adapters" then "welding 2.25" ears on an M-Caliper" then... naaaa, that's all kludgey, let's investigate a radial mount. Perfect.
* I can have LWB arms modified for the SWB application. - As it stands, this would be the best alternative to this kit we're producing. It would give you a more modern bearing and the factory 3" mounts. However, what sounds nice on the surface requires a lot of parts, skill, expertise and money.
So now that we know all of the pitfalls associated with getting a larger caliper on the rear of a SWB car, here are the benefits of this kit:
1. Factory Parts (basically...).
2. A true bolt on kit that incorporates all of the bits and bolts needed to get these calipers on your car.*
3. Larger rear pads to match any front caliper upgrades (A-Caliper or S-Caliper).
4. Larger 38mm pistons (like the 911S and 911L SWB models) for improved and factory 1.6:1 bias ratio.
5. A bolt on improvement that will not damage the integrity of your valuable SWB 911 whatsoever.
6. A pair of completely restored calipers. Fresh zinc plating inside and out. New 38mm stainless steel pistons and new ATE seals with proper square cut EPDM o-rings.
7. New caliper hard lines in factory OM steel with Cohline ends for a perfect fit.
8. Factory look through the wheels (you won't see any spacers or adapters or funky caliper locations).
9. You'll have vented rotors on the rear of your SWB 911.
10. SWB 911S and L owners will now have a larger pad in the rear.
11. Should be acceptable under most rules for vintage racing.
*this kit will require 944 rear rotors or the more expensive SWB vented rear rotors (at the time of this writing, around $450.00 each). The SWB vented rear rotors have the proper rotor mounting screw location to line up with you 911 hubs. The 944 rear rotors (@ $86.00) are indexed differently for those mounting screws but will work by setting the handbrake with a few open lug nuts. 944 Rotors must be turned down 2mm to clear.