When you upgrade to a 200R4 OD transmission to get the benefits of the 0.67 overdrive, it is rare that the automatic shifting sequence occurs at the proper speed. Most likely you have lower rear end gears and a cam so you want the shifts to occur at a higher RPM but the donor tranny is likely set up for a grocery getter and results in 1-2, 2-3 shifts way too soon for your setup. Thus you are stuck with manual shifting which is fun but there are times you want to set it in drive and run it automatically.
A lot of people suggest changing the shift points by adjusting the throttle cable. DON'T DO THAT! That cable needs to be set properly and left alone. It is the governor that sets the shift timing and you have to modify it.
We did ours on our '59 El Camino running a 307 w/ corvette cam; 283 PowerPack heads. We put 3.54 gears in the rear so our auto shifts were occurring @ ~1000rpm lugging the engine badly.
We bought a couple spare governors from PATC Automotive who specializes in 200R4 trannys.
I am giving them a plug because their authentic GM parts governors are less than $10! We bought two to play with.
It is a hassle to do this modification because you need to take the pan off to get at the governor. There are YouTube videos on doing that step so look it up if you don't know where the governor is. It is an easy swap. Here is a good video
Photo 1 shows the modified governor on the left and the stock one on the right. We took a huge amount of weight off the modified one (power hacksaw and files) but we took the design from a picture of a governor from a Grand National Buick. Plus we still have two more to play with if we screwed this one up. We cut half the skirt off the small weight and ground the top of the large one even with the top of the small one, about 1/8 inch.
Photo 2 shows an end view of the small weight. These things come apart very easily knocking out the pin at the base of the weights. Watch where the two ball bearings go! When putting them back together, 'glue' the bearings in their holes w/ Vaseline.
Photo 3 shows a couple more modifications we made. First we took out the spring in the big weight leaving the spring in the small one. We took our cue on this again from the Grand National Buick version. Second, we brazed a short nail in the spring hole in the small weight. Word is that that spring has a tendency to hop out on hard shifts so this is a common hi performance mod.
Photo 4 shows another view of the nail.
There are other sites on the web showing how to calibrate the speedometer by changing out the big plastic barrel gear on the shaft of the governor with the speedo gear that is removed by taking off the speedo cable at the back of the tranny. Do that while you are doing this. I think PATC sells the cheapest gears too. They have a ratio calculator on their site so if you know your tire diameter and rear end ratio, you get the perfect speedo ratio.
Oh, we ended with perfect shift points for the street; ~2000rpm @ 1-2 and 3000rpm @ 2-3. We haven't tried it yet but I assume at WOT the shifts will rise accordingly to higher in the power band.
I wrote an article on this in a Mid America Willys Club book many years ago but there is still interest in seeing what I did. Here it is.
The Julianos kit is based on a custom aluminum rail that is secured to the top then a plastic welting snaps over that rail to finish the look. It looks great when done right. Problem comes when the rail is riveted to the top. That makes it stand way too high and looks like a bad tupee. I sunk the rail part way into the trough around my top and it looks super.
Photo 1 shows a 1/8&quot; plywood sheet screwed and caulked in place. Also can see the aluminum strip I put into the channel to make it a little shallower.
Photo 2 shows a 3/32&quot; thick strip of aluminum screwed and caulked into the trough. The trough was a little too deep and this seals the bunch of staple holes the factory put there and gives the Juliano's rivets a good purchase.
Photo 3shows the beginning of the installation of the top after I painted the car. The installation goes per the Juliano's instructions from this point on. I cut two small pieces of the welt that I clipped on the rail. I put the rivets between these welt pieces. This way I was sure the rail was centered in the trough and the welt would fit snugly to the body rim all the way around. Note I also marked where the screws holding the aluminum strips are with a Sharpie so I didn't try to drill a rivet hole there.
Photo 4 shows using a putty knife to protect the paint while bending the Juliano's aluminum rail around the curved back corners on my Willys. The rail bends easily but didn't want to chance scratching the new paint.
You guys all probably know this so this is for me to remember what I did. Photo 1 shows a problem I had with the stock '59 Chevy gas filler door. The arrows show where paint was chipped because the door opened until it hit body parts. The side arrows were definitely chipped since the hit the sharp edges of the opening. The up-arrow is a potential chip since the door would slam against the under side of the fin. Name the cars you know that have downward facing painted sheet metal panels measured in square feet!!
Photo 2 shows the nifty fix I came up with. The 3/8" rubber hose stuck in the opening is the key. Just cut off 2 3/4" long pieces of the hose. Then with a screwdriver, mash the hoses in the two brackets shown @ the arrows. The hose slips way down in those brackets and is not coming out, it fits perfectly. Now the top edge of the gas door hits those rubber stoppers before any sheet metal interferes.
The car isn't that dirty; flash photography really exaggerates a little dirt!
The last part to modify is the '59 shroud that adapts the column to the dash real purty like. Photo 1 sows the first mod. You need to cut down those 3 ribs. They were sized to adapt the shroud to the skinny '59 column bu the '80 one is larger in diameter. Even with this mod, the sleeve is a really tight fit over the new column and that is why you need to cut off the plug mount, bolt bosses and slick it up as much as possible. Original ribs are near 1/2" tall, I cut them down to ~1/4". I tried a carbide burr but this is sticky pot metal and plugs up the burr. I finally got out the recipri-saw and using a long coarse carbide blade, sawed the ribs out. Probably the hardest part of the conversion. Shorten the mounting screws a like amount.
You also need to cut the notch shown in photo 2. This is needed to clear a boss on the '80 column shifter sleeve. I didn't see any other way around that interference. This is snuggled close to the dash and you don't even see it but without the notch there is a big gap between the two sleeves that is dirt ugly.
That's about it. I tried to think of other problems with the installation but with the mods described above, the thing goes in like it was made for it.
To install, slip the column in and bolt it to the dash and use the stock '59 'hose clamp' to anchor it to the foot-board bracket. You should have the sleeve installed loosely. Once the column is bolted in, hold the dash sleeve to the column and drill and tap a couple of mounting holes underneath and screw it to the column.
Photo 3 shows the electrical plug mounted to the column using a long wire tie on the bottom end and a 'finger' made of 16ga metal and mounted @ a column mounting bolt holding the top in place. Since we cut off the factory plug mount we had to do this. It's plenty stout and wil last forever. Also note we drilled a hole for the sheet metal screw to anchor the ribbed rubber kick pad at the bottom of the column.
We bought the IDIDIT wheel adapter kit that comes with the horn button adapter that adapts the '59 wheel to the '80 column and also the polished aluminum ring shown in photo 4 that fills the gap. We found that the ring was too thick so we filed the groove in the wheel very clean and square then sanded the ring to ~2/3 its original thickness. That left a thin hard rubber ring at the back of the wheel that stuck down about 1/16". That ring interfered with the guts of the column so we sanded it flush with the aluminum ring. Perfect fit.
This was a really easy conversion and I highly recommend it. As you can see we now can comfortably slide into the drivers seat and still have a stock look.
Items you will likely need are a new rubber seal for the pot joint at the bottom of the column (that is GM's name not mine! Comes up with some really interesting hits on a Yahoo! search!!), and new ball bearings inside the column. Both are available on the net.