1978 Chevy P10 Step Van Manual to Automatic Transmission Swap

[FFTravisM]

I am creating this thread for anyone of interest in what I needed and went through to get this done. I have a 1978 Chevy P10 L6 292 Engine with Clifford Intake and Headers, Weber 38 Carb (From Clifford). It had a Saginaw 3 Speed Manual Transmission Shift on column. Swapping to a 700R4 transmission. For note the rear end is a 4.11 ratio.

700r4 Transmission from Monster Transmission
Torque Converter from Monster Transmission
Classic Performance Classic Fit Steering Columns TC-6772-SB - Summit PN:CLP-TC-6772-SB
Classic Performance Steering Column Automatic Shift Linkages CPTSL - Summit PN:CLP-CPT-SL Qty 2
Lokar Hi-Tech Kickdown Kits KD-2700HT - Summit PN:LOK-KD-2700HT
Russell ProFlex Hose 632090 - Summit PN:RUS-632090
Russell AN to Inverted Flare Fittings 640331 - Summit PN:RUS-640331 Qty 2
Russell Transmission Cooler Line Fittings 640520 - Summit PN:RUS-640520
Russell Full Flow Hose Ends R10023B - Summit PN:RUS-R10023B Qty 6
ARP Pro Series Flexplate Bolt Kits 146-2901 - Summit PN:ARP-146-2901
Borgeson Universal Steering U-Joints 013449 - Summit PN:BRG-013449 Qty 2
Borgeson Universal Steering Shafts 409418 - Summit PN:BRG-409418

Schaeffer Manufacturing Co. 0204SAT-006S All-Trans Supreme Qty 3
Hayden Automotive 689 Rapid-Cool Plate and Fin Transmission Cooler
Advanced Tool Design Model ATD-5550 Automatic Transmission and Engine Oil Pressure Gauge Kit
ATP Y-816 Speedometer Cable
TADD TD2-3-6081X GM Turbo 350, TH 350 / 700R4 Transmission Slip Yoke 2-3-6081X (Same as Spicer just rebranded)
Spicer 5-153X U-Joint Kit Qty 2
Pioneer FRA-152 Flywheel Assembly
Spectra Premium CU162 Complete Radiator for Multiple GM Model Cars and Trucks
Transmission Mount
Lots of Blood, Sweat, and Tears.

When I took the drive shaft in to be shortened they checked it and it was 0.060" out. Max is 0.030". Which meant new drive shaft. Went from $125 to $300 quick but I tell you it made a huge difference. They also used the next notch thicker of tubing.

I am only to add notes on the tricky parts. You can ask questions on any of the rest.






Removal of transmission was pretty straight forward.
Once the transmission was out I had to remove the flywheel. This has 6 bolts and then 3 metal dowel pins. The manual recommends dropping the oil pan and drifting them in. This wasn't an option for me. The flywheel will come off with a few taps from the back side but leaves the dowel pins. I drilled them out and tapped. Then used a grade 8 bolt with some washers and a socket. I put the washers on the bolt then then put the bolt through the socket. Next started screwing it in to the dowel. used a ratchet and socket on the bolt and slowly pulled them out one by one. This saved pulled the oil pan and rear main seals. They recommend using new dowels when installing the flex plate. While reading "Chevrolet Inline Six-Cylinder Power Manual" they state on flywheels you need to use the dowels but on flexplates they have never seen the bolts backout even on dragsters running the 292's.




Once the transmission was installed re-positioned the transmission cross member support and drilled holes on the bottom. I couldn't get to the top holes. If I ever get the diamond plating off I may drilled them.






When I installed the steering column I custom cut the floor plate. The Steering column intermediate shaft was too short to work and mine was not adjustable any more. I ordered two U joints and the bar to create my own. This went pretty easy. I installed the U joints on each end and then used a wooden dowel to get close. Then took the metal bar and cut it to size. I lifted the front end and turned the steering wheel to make sure no binding. Your U joints need to be set up right or they will bind.




I decided to use braided cooling lines which are easily made. Cut to length install ends. I purchased a new radiator for the truck. It had a brass/copper original radiator. The new Aluminium radiators cool better and are thinner. For cooling I running from Transmission lower line in to upper Radiator transmission cooler, out bottom connection to auxiliary cooler upper connection then lower connection back to transmission upper connection. There is a lot of controversy about this. At the same time I decided to monitor the transmission temp since it's the easiest way to kill one. With this setup I have never seen it over 165F degrees.




Next was the shift linkage. With the step van column sitting far forward I ended up using two shift linkages. The second is really just for the shift rod. I used a HEX rod coupling nut to connect the two rods. I have only had to make one quick adjustment but installation was just following the instructions



The transmission has a internal lockout torque converter. Came as part of the transmission. Installed switch on dash and wired up. Very simple. I had to also run a new speedo cable as it was original and just a hair short.







Finally as for the kick down cable. The Lokar length worked good. Clifford has a carb adapter that works perfect for the weber carb and 700r4. I originally drilled a new hole on the throttle bracket but it felt as it was binding. I used the mounting bracket that came with the cable and added a bolt to mount it to the throttle bracket and it seems perfect.




I had to cover in the hole from the clutch linkage in the floor. Piece of rubber cut to fit. Since I had the truck out of service I had issues with the valve cover leaking. I replaced the gasket and added a 12Bolt Valve cover and side covers. Powder coated and installed.

First start up went good. Tried all gears with the truck chocked to prevent any accidents. Then started a idle moving. After running and getting the truck warmed up you need to add more fluid. It takes about 1.5qts more to fill the lines and two radiators.

I still have some minor Kick down able adjustments to make but it's been driving great. It was a lot of trial and errors. But a fun project.

[waco]

Thanks for the post
Your information will be quit useful in the next couple of years for me.
My current project is a 78 P10 with a broken/frozen/cracked block (292) and a 350 trans. I am replacing the 292 l6 with a 4.3 v6. The v6 came with a 700r4 and transfer case. After l complete the engine swap and get streetable, l will be installing the 700r4 in a couple of years. I just need to drive itto work out any suspension tweeks before I move on.
Again, thanks for the info.
Andy

[FFTravisM]

Your welcome. I am just happy someone can save some headaches.

[Aberdare]

Nice to see another P10 in progress...