I just finished installing a NV3550 in my 77. It originally came with a C4 and I was fortunate that my neighbor down the street wanted to convert his 3-speed 72 to an automatic. We just swapped parts... ;D I also have a 75EB with an AOD, so I wanted to do something different. I have been very pleased with the conversion and would recomend it to those who might be interested. I have listed some things below that I had to do. I did alot of research on past threads, so I do not feel that I can take any credit for the things I listed. Someone else did the work, I just put it all together. Thanks to MarsChariot for his Tech write-up and everyone else for posting their info, it was all very helpful.
Doug
• The fill/drain plugs on mine needed a 19mm allen to remove them. I made one out of a metric bolt with a standard threaded nut welded to it. Put a socket on that…
• Set the pilot bushing in as deep into crank as it will go to give you 1/8” – 1/4” inch more clearance. If you do not, there may be binding where the input shaft tapers back up in size.
• The pilot bushing needs to be soaked in oil overnight.
• I did not have to cut ¼” off the tip off my transmission shaft. I measures tolerances multiple times.
• I bench fitted everything together before putting the assembly in my rig. I put the transmission in first and then added the T-case.
• Buy an alignment tool for a 10 spline disk with a .75 inch diameter pilot bushing center
• I used a 164 tooth, 50 oz, 11 inch flywheel as I have a late model motor in my 77. I was told I could use a flywheel from an 87-91 F-series Truck with a 5.0. After I looked at a new one at NAPA (China), I elected to buy the one from WH which in made in the USA.
• I was told by my pressure plate supplier that the 76-78 trucks had a unique mounting bolt pattern for the pressure plate, most suppliers use a Chevy style bolt pattern which is more common. The WH flywheel was drilled for the unique pattern.
• I used silicon sealer on the flywheel bolts to the crankshaft; this is to prevent oil leakage and was recommended by my engine builder.
• I would recommend running a tap through all the threaded holes to clean up the threads. Do this in the bellhousing, transmission, mounting holes on the frame, etc. I used anti-seize or loc-tite on almost all of my bolts
• I bit the bullet and used the Chrysler trans fluid, you need 2.5 quarts to fill the transmission.
• I cut a 5 inch square hole in the center of the Trans hump on the body. It is a little larger on the driver’s side because of the existing transfer case shifter hole. I made a cover plate to screw down on the body over this hole as suggested in the NV3550 write up in the Tech section. In the front, I cut right up to the body support, but not into it.
• I cut an inspection hole on the driver’s side of the transmission hump with a holesaw; I then cut down the 5x5” piece I removed from the top to make a cover plate. This gave me access to the twin stick shifter mounting bolt.
• I used the twin stick boot from WH and I found a Hurst boot at AutoZone for the transmission shifter. The Hurst boot is mainly a dust/dirt boot, one day I will make a nice one like MarsChariot in the Tech write up. (Hurst # 114 7336, B1 boot and plate. Turn the plate over to not see the Hurst logo)
• With the 1 inch body lift in place, I placed the factory clutch rod next to the adjustable WH rod and made it 1 inch longer. This was my starting point for my clutch adjustments.
• I had to heat and bend (at the existing bend) my transmission shifter from A/A as it hit the dash pad. The first shifter from A/A did not fit my Trans, as mine had the square mount. A/A were very good to work with; they sent me the correct one and a return prepaid UPS label for the wrong one. They make 3 shifters, so you need to make sure to tell them what you have.
• The A/A NV3550 rear adapter now has 3 positions (threaded holes) for clocking the D20; you must use the center (factory position) hole in order for the WH twin sticks to work.
• I have a J-shift D20, the A/A kit is designed to work with the T-shift D20. With the J-shift you must use a twin stick set up. For my rig on the A/A T-case shifter mounting bracket: I had to drill a new hole ¾ “directly above the threaded hole A/A had put in their bracket. I then tapped that hole for a ½ x 13 bolt and used the pivot/mounting bolt that was supplied by A/A instead of the bolt that came with the WH shifters. (Same bolt, it just had the threaded end cut down.)
• With the A/A shifter bracket, I had to round off the top (shifter side) of the bracket for shifter clearance. Basically, 45 the corner instead of 90 degrees. I also had to notch the transmission case webbing just a little, near the top of the bracket support, for the proper fit.
• I had to heat and bend the twin stick shifters for clearance from the transmission shifter. This was done at the existing bends and it did not require a lot of movement.
• I felt most of the bolts supplied in the A/A kit could have been longer, there was room, I purchased longer grade 8 bolts and hardware. This was a personal choice and is probably over kill on my part.
• The supplied A/A crossmember was well built, but the paint was scratched up. I tried to do some touch up with some black Krylon and the factory paint lifted. A can of brake clean removed all of the factory paint and I repainted the crossmember.
• My catalytic converter had to be moved back about 3 inches, a short extension welded to the factory Y pipe and shortening the pipe between the Cat and Muffler.
• I ended up rebuilding my D20 so I upgraded with WH - HD output shaft. This caused me to have to shorten the rear driveshaft. When I got it to the Driveshaft shop I found out it was toast, so now I have a brand new one…
• Wiring: I had a C4 before my conversion and the neutral safety/reverse wiring harness went with the transmission to my neighbor. My 77 had a rubber 4 prong plug from the main harness to the C4 harness. Fortunately for me, I had another 4-prong plug in my box of junk. I wired the neutral safety wires together with this plug and extended wires down the transmission. I already had a GM Weather pack plug, which I wired up the transmission reverse light plug.
• I found, at least with my rig, that I cannot down shift the Trans into 2nd unless I am 20 mph or less. It grinds…
• The transmission feels good with 3:50 gears and 31x10.50x15 tires. RPM is around 1900 @65mph. I have a Carburetor now and I am looking forward to my EFI conversion this summer.
Doug
• The fill/drain plugs on mine needed a 19mm allen to remove them. I made one out of a metric bolt with a standard threaded nut welded to it. Put a socket on that…
• Set the pilot bushing in as deep into crank as it will go to give you 1/8” – 1/4” inch more clearance. If you do not, there may be binding where the input shaft tapers back up in size.
• The pilot bushing needs to be soaked in oil overnight.
• I did not have to cut ¼” off the tip off my transmission shaft. I measures tolerances multiple times.
• I bench fitted everything together before putting the assembly in my rig. I put the transmission in first and then added the T-case.
• Buy an alignment tool for a 10 spline disk with a .75 inch diameter pilot bushing center
• I used a 164 tooth, 50 oz, 11 inch flywheel as I have a late model motor in my 77. I was told I could use a flywheel from an 87-91 F-series Truck with a 5.0. After I looked at a new one at NAPA (China), I elected to buy the one from WH which in made in the USA.
• I was told by my pressure plate supplier that the 76-78 trucks had a unique mounting bolt pattern for the pressure plate, most suppliers use a Chevy style bolt pattern which is more common. The WH flywheel was drilled for the unique pattern.
• I used silicon sealer on the flywheel bolts to the crankshaft; this is to prevent oil leakage and was recommended by my engine builder.
• I would recommend running a tap through all the threaded holes to clean up the threads. Do this in the bellhousing, transmission, mounting holes on the frame, etc. I used anti-seize or loc-tite on almost all of my bolts
• I bit the bullet and used the Chrysler trans fluid, you need 2.5 quarts to fill the transmission.
• I cut a 5 inch square hole in the center of the Trans hump on the body. It is a little larger on the driver’s side because of the existing transfer case shifter hole. I made a cover plate to screw down on the body over this hole as suggested in the NV3550 write up in the Tech section. In the front, I cut right up to the body support, but not into it.
• I cut an inspection hole on the driver’s side of the transmission hump with a holesaw; I then cut down the 5x5” piece I removed from the top to make a cover plate. This gave me access to the twin stick shifter mounting bolt.
• I used the twin stick boot from WH and I found a Hurst boot at AutoZone for the transmission shifter. The Hurst boot is mainly a dust/dirt boot, one day I will make a nice one like MarsChariot in the Tech write up. (Hurst # 114 7336, B1 boot and plate. Turn the plate over to not see the Hurst logo)
• With the 1 inch body lift in place, I placed the factory clutch rod next to the adjustable WH rod and made it 1 inch longer. This was my starting point for my clutch adjustments.
• I had to heat and bend (at the existing bend) my transmission shifter from A/A as it hit the dash pad. The first shifter from A/A did not fit my Trans, as mine had the square mount. A/A were very good to work with; they sent me the correct one and a return prepaid UPS label for the wrong one. They make 3 shifters, so you need to make sure to tell them what you have.
• The A/A NV3550 rear adapter now has 3 positions (threaded holes) for clocking the D20; you must use the center (factory position) hole in order for the WH twin sticks to work.
• I have a J-shift D20, the A/A kit is designed to work with the T-shift D20. With the J-shift you must use a twin stick set up. For my rig on the A/A T-case shifter mounting bracket: I had to drill a new hole ¾ “directly above the threaded hole A/A had put in their bracket. I then tapped that hole for a ½ x 13 bolt and used the pivot/mounting bolt that was supplied by A/A instead of the bolt that came with the WH shifters. (Same bolt, it just had the threaded end cut down.)
• With the A/A shifter bracket, I had to round off the top (shifter side) of the bracket for shifter clearance. Basically, 45 the corner instead of 90 degrees. I also had to notch the transmission case webbing just a little, near the top of the bracket support, for the proper fit.
• I had to heat and bend the twin stick shifters for clearance from the transmission shifter. This was done at the existing bends and it did not require a lot of movement.
• I felt most of the bolts supplied in the A/A kit could have been longer, there was room, I purchased longer grade 8 bolts and hardware. This was a personal choice and is probably over kill on my part.
• The supplied A/A crossmember was well built, but the paint was scratched up. I tried to do some touch up with some black Krylon and the factory paint lifted. A can of brake clean removed all of the factory paint and I repainted the crossmember.
• My catalytic converter had to be moved back about 3 inches, a short extension welded to the factory Y pipe and shortening the pipe between the Cat and Muffler.
• I ended up rebuilding my D20 so I upgraded with WH - HD output shaft. This caused me to have to shorten the rear driveshaft. When I got it to the Driveshaft shop I found out it was toast, so now I have a brand new one…
• Wiring: I had a C4 before my conversion and the neutral safety/reverse wiring harness went with the transmission to my neighbor. My 77 had a rubber 4 prong plug from the main harness to the C4 harness. Fortunately for me, I had another 4-prong plug in my box of junk. I wired the neutral safety wires together with this plug and extended wires down the transmission. I already had a GM Weather pack plug, which I wired up the transmission reverse light plug.
• I found, at least with my rig, that I cannot down shift the Trans into 2nd unless I am 20 mph or less. It grinds…
• The transmission feels good with 3:50 gears and 31x10.50x15 tires. RPM is around 1900 @65mph. I have a Carburetor now and I am looking forward to my EFI conversion this summer.
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