The Camp 4x4 Bus - 1973 Suburban 8.1 Swap & Build

[camp4x4]

If I do need to pull a gauge cluster I may just roll up to Newark and pull a whole list of things from this guy:

http://row52.com/Vehicle/Index/1G8GC26W3GF102147

- Hydroboost brake booster
- Steering column
- Gauges
.... other stuff maybe.

 

[FBJR]

https://williamsport.craigslist.org/pts/6053955667.html

https://seattle.craigslist.org/sno/pts/6130700272.html

https://stockton.craigslist.org/pts/6079616593.html

These are getting pricey and harder to find.

 

[Larry]

Oh, something else "fun" dawned on me while removing things connected to the engine as we pulled it: my oil gauge is the old tube to the back of the cluster type... Doesn't look like the electric model will swap straight over so I gotta figure out the cheap(est) way to square that away... I'm thinking of pick-n-pulling a post-77 cluster... hmmmm

You can still use that cluster. Try moving the brass fitting from the back of the 350 block and see if it will screw into the 8.1 and just run a mechanical oil line just like before. If the fitting won't fit the 8.1 block I bet you can find some conversion fittings somewhere. The 8.1 does not need the oil pressure sending unit to run anyway

 

[Larry]

I just ran out to the garage and screwed an old GM manual oil pressure fitting into an 8.1 block with an adapter I had laying around. 1/4 to 3/8 I believe. You should be able to find an adapter like this easily and not have to spend any money on a cluster. Same with the temp gauge. Use the same wiring that went to the 350 sending unit and screw that sending unit into the port in the drivers head. The actual coolant temp sensor for the ECM is on the passengers side head. No need to swap a later cluster or do any of that Dakota Digital B$. These engine swaps are not nearly as difficult as many make them to be

 

[camp4x4]

I just ran out to the garage and screwed an old GM manual oil pressure fitting into an 8.1 block with an adapter I had laying around. 1/4 to 3/8 I believe. You should be able to find an adapter like this easily and not have to spend any money on a cluster. Same with the temp gauge. Use the same wiring that went to the 350 sending unit and screw that sending unit into the port in the drivers head. The actual coolant temp sensor for the ECM is on the passengers side head. No need to swap a later cluster or do any of that Dakota Digital B$. These engine swaps are not nearly as difficult as many make them to be

View attachment 401254

Nice, thanks Larry, but getting rid of the oil line into the cab (potentially leaking all over) is another reason to switch gauges. Definitely not a "have to do" thing, more of a "want to do." And since I'm already doing a pretty extensive set of tweaks anyway... why not. Likely I'll just find a pick-n-pull truck to grab one from. $40 is no biggie for the whole assembly. While one with a tach would be rad... not really necessary. Based on this info from 73-87.com it looks like a '78 and up tach dash would work.

 

[FBJR]

I had my 77 for 30 years, it never leaked but was a pain to unhook when working on it.

If I recall and Larry can verify I think the 90-91 dashes were diff and went to a dig speedo and the bezel is diff for the 91 subs around the radio.

You might be safe with an 87 or earlier. I have to be careful getting parts as 87-91 for the subs and 2500-3500s stayed square body until 92.

 

[Larry]

Nice, thanks Larry, but getting rid of the oil line into the cab (potentially leaking all over) is another reason to switch gauges. Definitely not a "have to do" thing, more of a "want to do." And since I'm already doing a pretty extensive set of tweaks anyway... why not. Likely I'll just find a pick-n-pull truck to grab one from. $40 is no biggie for the whole assembly. While one with a tach would be rad... not really necessary. Based on this info from 73-87.com it looks like a '78 and up tach dash would work.

Oh, okay…the way your first post on the cluster read I figured you weren’t too excited to replace the cluster. For what it is worth, I’ve been wrenching since I was a kid at my dad’s shop in the 80’s and I have yet to ever see a mechanical gauge or copper tube leak (unless someone did something stupid to the tubing routing) although I have seen many of the late model oil sending units leak right out of the plastic body. In fact, the later model sending units like the LS engines and 8.1Ls use are some of the biggest offenders for leaking at the body. I had a Tahoe that used two if them in 8 years. Also, if you ever ran into any oil pressure issues on a vehicle the first step is in diagnostics always to remove the oil sending unit and plug in a mechanical gauge to verify oil pressure. Something to think about…..

I had my 77 for 30 years, it never leaked but was a pain to unhook when working on it.

If I recall and Larry can verify I think the 90-91 dashes were diff and went to a dig speedo and the bezel is diff for the 91 subs around the radio.

You might be safe with an 87 or earlier. I have to be careful getting parts as 87-91 for the subs and 2500-3500s stayed square body until 92.

Yeah, the square body clusters changed in 1990 to VSS instead of a speedo cable. So basically a 78 to 89 cluster would work providing the harness plug on the 73 lines up correctly with the printed circuit on the later cluster. My 78 K10 happens to have the same 1989 cluster as my Suburban and it was plug and play. Not too sure a 1973 would be though. If it were me and my truck had an original mechanical gauge, I sure the hell would keep it! :coffeedrink:

 

[camp4x4]

Yeah, the square body clusters changed in 1990 to VSS instead of a speedo cable.

Actually, since I have to create a VSS signal out of the transfer case for the PCM to run the 4L80e I have a Dakota Digital in-line signal generator and universal signal interface. The interface has ports for connecting up to 5 outputs. So I could switch to using a VSS speedo instead of cable. #options....

 

[Larry]

Actually, since I have to create a VSS signal out of the transfer case for the PCM to run the 4L80e I have a Dakota Digital in-line signal generator and universal signal interface. The interface has ports for connecting up to 5 outputs. So I could switch to using a VSS speedo instead of cable. #options....

Yep, lots of ways to skin a cat. You could switch a VSS speedo if you really wanted to…. Not sure it would be worth the hassle IMHO when there is no real need to do so. Sounds like a good way to spend a lot of money you don’t need to with no real big benefit in the end.

However, I’m planning on using their (or Howel’s) speedo cable pulse generator on my Suburban so I can add the GMT400 style Electromotor Cruise control system. That is a very easy way to add cruise control when using the L29 mechanical throttle body on the L18 8.1L. Basically, I’m going to run the cruise just like a 1999 L29 Suburban except the pulse will come from a cable driven pulse generator instead of a VSS sensor.

These are neat. Not sure how durable they are though.. time will tell

 

[camp4x4]

Another day, and more progress. Couple hours of work last night saw the axles removed. And parts keep rolling in the door. Today brought these super trick Taylor spark plug wires. In the second to last shot you can see the years of gunk built up on the transfer case. That thing is getting a power wash and a full tear down. Last shot is of the worst of the frame rust. Not bad at all really. Should easily clean up. Next few weeks are gonna be slower going with less major changes. Gonna pull all the lines off the frame, clean it, prime and paint. Front wheel wells and misc metal parts will get the same treatment so everything is shiny-ish going back together. After talking it over with my buddy Rodney, I decided to stop short of a full body-off approach. We deemed it to time consuming and really too space consuming to split the body and chassis. I think in the end having it so far off the ground on these amazing 12Ton Harbor Freight jacks will be plenty to give me working space. I'll likely pull the whole gas tank while I'm at it to make sure it's really down to just the frame and body when I put on the undercoating.

Trick Taylor Cables


Sweeeet!


Axles on their own


Sans Axles


Nasty NP205


Frame rust - Looks bad, but really it's just surface.

 

[FBJR]

Wish I could find side sliders or rear flip-out windows.

 

[zoomad75]

Cool build! Nice to see somebody build one since Don was hiding away from the public! A little tidbit on the cluster issue. It is NOT plug and play to put the later cluster in where the original 73 cluster came from. The big issue is the 73-75 clusters all had an Ammeter instead of a Voltmeter. Sure the later one will plug in, but you will melt that sucker down for sure wiring a Voltmeter in like the ammeter goes in.

On my old 75, the Ammeter was shot to start with. I picked up a 76-80 voltmeter off of ebay for cheap. The way I installed it was by omitting the spring tabs that connect the printed circuit to the gauge. I then added ring terminals to indivdual wires and ran one to the positive and negative side of the gauge. The positive wire ran to the fuse panel on an open port and the negative went to the ground tab just the left of the cluster on the body. Worked just fine.

The oil pressure gauge on my 75 was just like yours, mechanical. During the entire time I ran that truck I never once had a leak from it. It was just as sensitive to changes as the autometer sport comp mechanical gauge I put in my 69 Nova. Food for thought. My 91 K5 with an LS swap is using the stock gauges (electric speedo) and the only gauge that don't work right now is the dang oil pressure gauge. I've run through the GM diagnostics for it and the sending unit is the culprit. It's really personal preference.

You are moving fast for sure. Keep up the good work!

 

[zoomad75]

Nice, thanks Larry, but getting rid of the oil line into the cab (potentially leaking all over) is another reason to switch gauges. Definitely not a "have to do" thing, more of a "want to do." And since I'm already doing a pretty extensive set of tweaks anyway... why not. Likely I'll just find a pick-n-pull truck to grab one from. $40 is no biggie for the whole assembly. While one with a tach would be rad... not really necessary. Based on this info from 73-87.com it looks like a '78 and up tach dash would work.

Ask and ye shall recieve...I happen to have a factory tach cluster for a 78-80. Complete with the separate tach harness and the cluster connector with the first few inches of wire to allow for splicng or moving terminals. A little time comparing the terminal locations from the 73 to 78 and you can repin the connector to fit your needs with the electric oil pressure. Oh the printed circuit is MINT too.






PM me if you are interested and we can talk price.

 

[Funrover]

Pretty sweet project you have there!

 

[chilliwak]

Ya just got to love a classic `Burb´build....:drool: