The Stovebolt Site Forums Project Journals Project Journals 1947 Chevy Panel Truck Frame swap with 1988 K2500

I’ve been slowly working on various things getting this closer to get on the road. Steering wheel modified to transition to the ‘80’s column, painted and the horns work. All lights work as they should except for the original rear light on the door. I need to find the contact plate. I mounted the interior sun visor yesterday on the driver side. For the passenger side I’ll mount the seat first so I have a place to sit. Slow going with the speedometer and gauges, but I’ll figure it out eventually. I removed the car tent so it's out in the open from now on.

I drove the truck to the auto parts store and back! It made the trip with no troubles other than the steering feels funny, and the shifting doesn’t feel right. When I first attempted to drive I pulled out onto the road and the it felt like the steering wheel was loose and it seemed to re-clock 90 degrees off. I checked the steering column and linkages and nothing is loose. I re-clocked the steering wheel, but I’ll need to do it again. It rode down the road straight and I was able to steer, but it just doesn’t feel right. May be due to the original steering wheel with the power steering ratio feels touchy. For the shifter, it may be that the clutch was not moving far enough. It wasn’t grinding, but I didn’t get the feeling of pushing it into a gear and then feeling it drop into place, it was just push it into gear, hard to describe. I have since adjusted the clutch pedal linkage for more engagement. I do not know the condition of the clutch disc, it worked before the build. Next trip will be to the tire store.
I finally got the speedometer drive working after how many years. Still need to troubleshoot a signal in the truck getting to the controller. Passenger seat mounted, and the interior sun visors in place. I made a box for the heater blower motor speed resistors to mount in-line on the duct.
Still have a long list of things to do, but at least I’ll be driving along the way.

I somehow managed to convince my son to ride to the tire store with me. He was hating me the whole way. It was loud. They didn’t have what I was looking for so I made an appointment for the next week. Oddly, going over the speedbumps at the mall parking lot felt like nothing. The old tires LT215/85R16 Load Range D at 35psi and the ¾ ton suspension of the donor ’88 K2500 is a softer ride than the ’47 1-ton. I had previously run these tires on the original frame and it was stiff. I had been looking at options for a softer tire and found only 2 options for the size I wanted. The LT215/85R16 (30.4”x8.5”) commercial traction Load Range D, like I had, and the P225/75R16 (29.3”x8.9”) Standard Load at 40psi. max. The tire salesman suggested the 235/75R16 (29.88”x9.25”). He gave me an estimate sheet that I later noticed was for the 225/75R16 tires. I went to a used tire shop to get a spare for a test fit, that is when I noticed the size on the estimate. The spare fit, so I got new tires from this other shop the next day. The steering tightened up with the new tires. These are Load Range E at 80 psi and yet the ride is soft. The suspension makes all the difference.
Now I need to get the floor mat installed for a quieter ride. Before that the transfer case shifter needs the bezel installed. I don’t like the angle the shifter is at in 4 low, so some heat and a pipe wrench to change the angle. Time to paint it too. I also found the shift tower bolts loose again. I made some spacers <0.275” tall to give the shift tower bolts something to snug up against. This is the 1988 (HM290) 5LM60 transmission, I’m guessing the first gen. The original tower gasket was deteriorated. I got the replacement as was listed for the NV3500. It seems the later versions had some sort of spacer included on the bottom of the shift tower. The NV4500 has larger holes and spacers with the bolts. I don’t know how the first gen HM290’s were originally set up. I hope this fixes it.

I’ve been driving and working on this, but not as much as I’d like. I repaired the floor panel over the transmission and painted. I installed some sound and thermal barrier on the floor and toe board along with the under mat and floor mat. I sure wish I had put something more under the firewall mat. I still need to figure something out for under the seats. I get a bit of road noise through the floor, and engine noise through the firewall. With the cooler weather I mounted the temp controls. Added a radio in that bracket too. I made that bracket to accommodate the A/C unit as well. I needed to mount some dummy lights so I made a bracket for below the gauge cluster. It includes the turn signal indicators, Battery, Brake, and CEL.
I have been working on the Gauge Cluster. The original gauge cluster doesn’t have much to offer except the look. The oil and temp are mechanical, the donor is electrical. The gas gauge is the wrong scale for the donor sending unit. The Battery gauge is the only one that could work as it is a current meter. Since I’m swapping out the other gauges, I’ll do them all. The donor gauges are big. I tore down both clusters to see what I have to work with. I started to fit the donor gauges to the original housing. I made a template from a to-go lid to identify where the gauge needle pins are located. Things went sideways here and I had to back up. I cut some holes in the original cluster can and soon discovered the donor gauges are too big to get the needle pins in the same place as the originals. I thought about it. The way the original is assembled, I would need a bracket to mount the donor gauges to. I made a bracket and placed the donor gauges as close together as I could.
I’m trying to get everything lined up, but there is too great of a margin of error with the hand tools. The gauges are not perfectly aligned with the holes in the bracket, but close enough. Next is to locate the gauge plates. I had purchased another gauge cluster for parts, I’m using it for this measurement. I cut a ring that matches the outer diameter of the gauge plates and taped the plates to it. Aligned the plates to the needle pins. Marked the holes, drilled them, and installed some M2 bolts. I then mounted the plates to the bracket. Now I could see how the donor gauges will meet the gauge plates. They are too far out to have the same stop as the original. The original gauges needles have a dog leg that meets the contour of the slot in the plates. This acts as the stops and keeps the needles from swinging off the face. I wanted to use the original needles for this purpose, but I’ll make it work as it is. I’ll use the plate bolts as stops and make my own needles. I removed the brass hubs from the donor needles, and placed them on the gauge pins. They are too tall, and the plate bolts are also too tall. I placed the gauge label piece to see the fit. I cut the needle hubs down.
I cut some needles from some hobby stock. I soldered the needles to the hubs, and bent the needles over. The test fit of the needles revealed that the contours need to be trimmed. I suspect I’ll need to add some ballast to the back side of the needles as both the donor and the original mechanisms had such, and I’m running two of these gauges upside down. The bolts I have for the gauge plates are M2 12mm. I need about half that length, but the local fastener shop has only 10mm. I “cut to fit” the bolts that I have. Now the gauge label piece sits down as it should.
I made a paper template to place the holes for the ½” standoffs to mount the gauge bracket to the cluster can. The cluster can has Two backlights. There is a baffle next to each light, it is about ½” tall. With the gauges mounted to the can, I’m one step closer. I made a circuit board out of prototyping board and soldered the gauge sockets to it. After plugging the gauge cluster to the circuit board, I cut down a coffee can to use as the rear housing. I’ve refaced the gauge plates. Next step is paint and wiring.

That gauge cluster looks great. Do you have a picture of the completed face? Real tedious work but great job!

Thanks!
Over the winter break I made a calibration box to get the needles on the right way. I found the values on-line for what the gauges should be reading.
For Truck Years: 1979 - 1990
The Temp Gauge Needle Should Point to:
Left Line (Cold) when sender resistance = 1,365 Ω
Middle Line when sender resistance = 96 Ω
Right Line (Hot) when sender resistance = 55 Ω
'87 FSM Electrical Diagnosis Service Manual Supplement:
Oil Pressure Sender:
90-ohm at max pressure
0-ohm with no pressure
Fuel Gauge Sender:
0-ohm at empty
90-ohm at full
From this it looks like the temp sender is logarithmic. I think the oil and fuel senders are linear. I made a calibration box with parts I had on-hand. Unfortunately I didn’t have the exact value pots so I put a resistor in parallel on each. This made their sweep logarithmic. Double unfortunately the pots that I had closest to what I needed have detents so I was unable to get an exact adjustment to the values I wanted. They are close enough. The calibration box has an input from a power supply, three pots for the three gauges, and a wiring harness to my cluster. I measured with an ohm meter to get close to the center values of Temp: 96 Ω, Oil: 45 Ω, and Fuel: 45 Ω. I then attached to power supply and gauge cluster. With 12v input I attached the needles at the center position. I tested at 14v and 9v, and swept through the range of each sender. I adjusted the needles as needed. Unfortunately the oil and temp movements were reverse since I’m using the gauges upside down. I spent a few days learning about gauges and playing around with trying to modify the windings to reverse the movement. In the end swapping the two gauges worked, a simple solution. I have yet to install the cluster in my truck and I may try to modify the needle balance as the needles drop when not energized.

I didn’t have the gasket for the gauge glass, but I installed the cluster anyway. It was even harder to get the nuts on with that can on the back. It’ll come out again to add the gasket and add a way to keep the gas needle from dropping so low when de-energized. The truck was down for awhile while troubleshooting a gas leak. I finally found the tank had a crack under the foam gasket. That was on the top and was hard to find until I filled the full 34 gallons. I pumped all that out into Two other vehicles and a couple cans. My FLAPS got a replacement tank for me. I had been saving an old bike innertube for a decade and used that for the new tank to frame gasket. I’m still trying to figure out the fast flashing turn signals. The flasher relay is electronic and does flash slow on my other truck. I’m getting to drive the truck more than work on it, so that’s good. The steering is still feeling tight. There is a bushing where the shaft exits the column. The bushing is stationary. The cup joint contacts the bushing and binds. I was able to push the bushing up into the column to gain clearance. I’ll see if it stays out of the way, or if I need to fashion a way to keep it in place.

I had been driving a couple times a week, weekend errands, and one day to work. I added a washer between the steering column and the intermediate shaft. It seems to bind after driving for awhile, I think it’s heat related. I looked into replacing the bushing with a bearing but found no clear swap. The column would need to be modified. I may do that yet, but first I think the lower intermediate shaft may need attention. The rag joint is at the bottom by the steering box. The steering column comes at a different approach than the donor, so I pulled the intermediate shaft up. It now has about 10 degrees difference. That is by flexing the rag joint, I don’t think that is good and it may be adding contention to the bushing. I’ll add a u-joint there.
I’m gathering the parts to add A/C. I had purchased a compressor from the pull it yard a few years ago. I need to swap out all the 4-rib pulleys to 6-rib. I went to a local machine shop and had them press out the old bearing from the A/C pulley. As I was leaving, I tried to start my truck but nothing happened. I could hear the main relay click when I turned the key, but the gauges weren’t responding. I cycled the key a few times and finally the voltage gauge came to life. I’ll need to troubleshoot that.
I haven’t driven since then, but I did get the lower latch catch for the barn door. Thanks to ranchojuan for the part.

For future reference, when I installed my rebuilt speedometer, I used knurled nuts instead of hex nuts. It was SOOOO much easier getting those nuts installed with two fingers instead of a socket wrench.

I even used knurled nuts to put the radio grill back on.