I did the 130 amp 3G alternator swap a few years ago on my '67 Shelby drag car and I'm totally happy. I'm lucky to have a friend who's family runs a good local starter & alternator rebuilding company and he set me up with my first 3G alternator, so I didn't initially have an exact application, but he knew I wanted the one that was closest to the original FE mounting and knew exactly what I needed. I have the two ear "pivot" mounting with 7" spread between the bolt holes. I just took a look at the box it came in and it is marked "7765-7" which seems to match the info in the last link 66Ford supplied. Mine has the one threaded hole, but as mentioned in the above links it will be metric thread. I made a custom mount since I am using a Meziere electric water pump which doesn't have the mounting holes a stock style Ford FE water pump will have. I am going to be using a 130 amp 3G alternator on the '67 Cougar I'm building, but I will be using one of Jay's water pump adapters for the CVR electric pump that have the alternator mounting bracket holes. I think the 3G's that have the 7" spread work best for my applications, but the ones with the 8+" spread may be better for some people, it will depend on what you intend to use for brackets. The links 66Ford supplied have some good application info, I've been watching while out in the salvage yards and what I spotted that matched the 3G's I have were the Taurus, but you can see there are others.
I'll add a couple things, just for people looking to do this swap on their old Ford - You'll probably want the special wiring plugs that connect to the alternator. One of the links 66Ford supplied gives some info on what to get, my buddy gave me the first one I used, but I've since been watching the U-Pull-It lots. If you're a budget minded person like me you can snip the connectors off any 3G you find, but I've noticed some Ford trucks will have a pretty good wiring harness all ready made and ready to go. Here is a picture of a couple alternator wiring harnesses. Sorry I don't have an exact application, I just grabbed stuff that looked like a good donor, but I believe the longer ( about 36" ) wiring harness came from a '90's full size Ford pickup. The shorter ( about 24" ) harness I think came from a '90's Ford Ranger pickup. Along with the needed plugs for the alternator they include a nice heavy gauge wire that goes from the alternator to the starter solenoid you will need. The shorter one will work perfect for typical FE's that have the alternator near the starter solenoid on the passenger side inner fender. Many of the other original 3G applications use a much longer heavy wire that crosses the whole engine compartment.
![](http://www.supermotors.net/getfile/1107200/fullsize/3g-alternator-ford-wiring-001-rs.jpg)
Here's a close up picture of the wiring plug end. You will also get a nice rubber boot that slips over the heavy wire's connector with the factory harness.
![](http://www.supermotors.net/getfile/1107201/fullsize/3g-alternator-ford-wiring-002-rs.jpg)
My other thought - the 3G originally used the serpentine belt and the parts store or salvage yard alternator will probably come with that style pulley. If you will be converting to a V-belt know that the alternator pulley shaft can be a little short compared to what our old 1G alternators had. I mention this because the 3G at high output will really need some good belt grip! I found you will probably need either a 2 v-belt pulley, or a larger diameter pulley that gets more belt contact. Many of the 2 belt smaller diameter alternator pulleys do not have a deep enough recess in the center to get the nut on the 3G alternator shaft, but they do make them. I ended up using a large 4" diameter "Hi-Po" style single belt pulley like the Mustang resto places sell on my Shelby, since that's what I had on hand, but I intend to use a 2 belt pulley on my Cougar.