This is the follow-up to my request for information. I feel that if you ask for info on a web board you should post an answer if you get one. Short story, it is possible to put an Explorer 5.0/4R70W in a ’66 Mustang in OBD2 trim without a distributor and without changing to a Mustang computer. It is possible to get the PCM programmed to a non-emissions version and delete PATS. It is possible to use the Explorer front cover and a front sump dipstick. It’s not running yet, but it won’t be long.
Long story. I started with a ’66 Mustang with a not-quite-running ’88 Cougar 5.0/AOD conversion I started 15+ years ago mentioned in the top post. Last year I picked up where I left off and made improvements. Battery relocated to trunk. Shortened 8.8 Explorer rear. Borgeson steering. Etc. Was to the point of hearing it run, but was not happy with the prospect of the Cougar 5.0 and it’s 150HP. When the injectors were bad after sitting 15+ years and I noticed the TV cable to the transmission was not connected to the throttle body (bushing gone), I drew a line in the sand and said no more-but I did borrow a set of injectors so I could hear it start and it did. Pulled the engine and transmission and sold them. I wanted an Explorer 5.0 with the improved 4R70W transmission. I bought a wrecked AWD 5.0 2000 Mountaineer. I bought a 2wd transmission from the pick-a-part. I sent the PCM to “The EFI Guy” Garry in Colorado. He is the key to all of this. He turned off PATS, EGR, and all the fuel tank sensors. I pulled the PCM from the yard-driving truck and sent to him. He turned it quickly and I was able to put it back in the truck and drive it into the shop to pull the engine. Removed the main engine compartment wiring harness from the C115 engine connector. Since it was wrecked and the front end, radiator, and condenser was ruined I cut most of the nose off with a Sawzall. Disconnected the transmission from the transfer case (you really need a ½” half-moon wrench for this-OR-pull the access cover). Pulled the driveshafts and then transfer case. Cut the exhaust off (try to get the passenger side as high as possible so it clears the motor mount coming out). Disconnected the remaining lines to power steering and unbolted the motor mounts. Dropped the transmission crossmember and it was ready to come out. There is no good way to grab it. I ended up with straps around the exhaust manifolds. Glad it didn’t have to go high. After that it snakes out and there you go.
I had already pulled the old 5.0 so then I started changing things left over from the Cougar 5.0 to the Explorer 5.0. Bought HiPo exhaust manifolds that I am told are required to run GT40P heads so I pulled the Explorer manifolds and installed them. Put new spark plugs and wires on while I was there. You can use earlier style lift loops on the exhaust manifolds (mine came from the ’88 Cougar) when you put it back. Pulled the AWD transmission and replaced it with the 2WD one (with new front seal “while it was out”). I should have done the oil pan while the transmission was off, but I didn’t. Pulled the oil pan and figured out the dipstick. You have to keep the Explorer timing cover and unique accessories to stay distributorless. Drilled a hole on the LH side of the timing cover and put a flexible dipstick in the only place it fits. There is not “meat” here on the right to drill for a dipstick like the ‘80’s style cover has. I had to get creative. I ended up JB Welding the bottom of the dipstick tube to the cover and had to cut notches into the p/s bracket for the tube to get to the top. I bought a generic flex dipstick, get the longest one you can so you can access it. After that, swapped a new oil pump and pickup and installed the front sump pan. The FelPro 1-piece gasket with easy-ups worked well. So 2000 5.0 Explorer style oil pan and exhaust gaskets worked fine with the early pan and HiPo manifolds. Used stock 289 Motor mounts and AOD conversion transmission crossmember and mounts that I already had. Used an early Mustang II floor shifter and shift rod (that’s what I had), and the Explorer shift tab. Had to heat and bend the rod to make it fit. Took the ball off the Explorer shift tab and drilled it out to use the press in bushing. The transmission connector cannot stay with the stock bracket, but it will go in on top without “dimpling” the floor or changing wire lengths. I have a Borgeson power steering box (no issue with HiPo manifolds and automatic) so the return line hooks right up. On the pressure line, I have an Isuzu Trooper line at the box spliced with a JIC fitting to the Explorer hose from the pump. I had the Cougar 5.0/AOD in with a 49” (’88 Cougar) driveshaft. It was tight on clearance, but kind of worked. The 4R70W appears to be an inch longer so I seem to need a 47” or 47.5” shaft. Looking at ‘90s std cab automatic Rangers that are supposed to have 47.5”. That is the mechanical side of the swap. With that, the engine is in the car.
On the electrical side, I am using the engine/ transmission harness from the Explorer with only 2 changes. 1-removed RH rear O2 sensor wiring to the transmission plug. 2-used LH rear O2 sensor wiring to get VSS up to the PCM. I am adding an old-school Ford VSS generator and keeping the cable speedometer. This only applies to the ’98 up transmissions if you want cruise (no VSS in transmission, in these VSS is generated in the rear axle and passes through the ABS module to get to the cruise control). Garry has YouTube videos on modifying these harness if you really want to streamline it. I elected to leave the C115 connector alone and take the mating front harness out of the Explorer and use it- you do have to pull the dash to remove the dash harness, but it is not hard. It has a nice fuse/relay box that is way overkill for a Mustang. I am using it and an aftermarket harness for the Mustang to keep the electrical loads controlled. The factory Service manuals for 2000 (and 1996 supplement) have nothing on the 5.0 so don’t bother with them. The 2000 Explorer/Mountaineer wiring diagram manual is good. I did a lot of wire tracing and thinking to get it where I can use the Explorer front harness mated to the aftermarket dash and rear harness. I left the front O2 connections in the stock locations. The RH side could be longer and access better, but it will work as-is.
Fuel system. I have a Tanks Inc. 22 gal 69-70 style fuel tank with Walbro pump. I am using canister purge and a 2000 Mustang charcoal canister mounted where the battery was. The ’99 up 5.0 is “returnless fuel”. There is a regulator in the tank that returns fuel inside the tank (contrary to rumor it does not vary voltage to the pump). There is enough height on the pickup to add it (but maybe not on a 16 gal tank, I don’t know) but not enough room to get it through the opening in the top of the tank. So I am using a 2000 Corvette fuel filter (Wix 33737) that has a regulator built in it and a return line to tank. Or you could just have an external regulator and normal filter. One additional advantage of the Corvette filter is that it is 5 micron where the stock Explorer filter is 10 micron.
The PCM either goes nearby the engine or you can extend the harness and put it inside. I elected to not extend it. I bought a 2001 Ford Escape PCM box from the pick-a-part (note: rear is held in under the cowl, not from inside the car). I cut a hole in the firewall and mounted it. I will have to patch up where the Cougar harness went in, the PCM box can’t go in the same place.
There is no room for the stock a/c compressor without major shock tower surgery. Again, you have to keep the Explorer accessories to stay distributorless. Everything else fits nicely in the Mustang engine bay. I got an oil filter adapter to use a FL1A filter because I was told the Explorer one wouldn’t work, but the non-oil-cooler Explorer filter housing puts the filter in a nice place so I left it. This Mountaineer had an a/c eliminator so I didn’t have to buy one. I have seen a routing with a shorter belt that would allow no eliminator. Investigating whether a 2000 Crown Vic a/c compressor with top fittings might fit the Explorer bracket correctly. If it does, it will require relocating the p/s reservoir.
The IAC valve is the tallest thing on the engine. I found CobraEngineering that offers an IAC mount where the EGR valve once was, but it is not exactly the right bolt spacing. If the IAC can’t be relocated, you will need a raised hood. I ended up with a Cobra Engineering IAC blockoff plate. Then I will put a threaded plate with a nipple where the EGR valve was. I will connect that to a BMW/Volvo/SAAB remote, PWM style, IAC valve (Bosch 0280140516). I believe that the Holley Sniper remote IAC valve would also work and already has a filter.
I will probably use an aluminum '69 Mustang BB Radiator. Looked long and hard at crossflow from '68 BB Galaxie or 5.0 Fox Mustang but there is a lot of fabricating to mount and they are wide. I have enough space to use the Explorer mechanical fan, but will likely use a 2-speed '95 Taurus fan or '90s Volvo fan with Volvo relay and BMW switch. Unfortunately the PCM cannot be made to control an electric fan.
I hope to have it running in a month or so. I will post another update then.