Re: Scott's 1972 Chevy K-20. A place to start.
 

Thanks Nick, appreciate the fact that my free time means more updates on the site. I actually have a plan to get it all done by the end of the year. As far as the temperature goes, I'm OK with 102, just not in May.... I don't like seeing triple digits until June (but I guess we're almost there).

Hopefully, I'll get some more updates in here after this weekend, and try to include as many pictures as possible. My wife's looking forward to parking in the garage again, as her new car hasn't seen the inside of the garage since we bought it...

Re: Scott's 1972 Chevy K-20. A place to start.
 

Nice project, thumbs up on the Cummins swap, doing a swap myself in a 82 K30 that had a 6.2.

What trans are you using? What year is the dodge?

Re: Scott's 1972 Chevy K-20. A place to start.
 

1994 Dodge

Engine:
5.9L Cummins I-6 with a Bosch P7100 injection pump.

Driveline Specs
Transmission: 47RH four-speed automatic. 1st 2.45; 2nd 1.45; 3rd 1.0; 4th .69; R 2.21
Transfer Case: NP241DLD 2.72:1 low range.
Front Axle: Dana 60 (248FBI) 3.54 gears
Rear Axle: Dana 70 (267 RBI) 3.54 gears

Re: Scott's 1972 Chevy K-20. A place to start.
 

Man! i read through your thread a while back but missed when you decided to go for a diseasel. now i am 'scribed!

Randy Ellis! that is awesome! looking forward to what they cook up for this bad boy.

Re: Scott's 1972 Chevy K-20. A place to start.
 

Well, I've always wanted to go diesel, just never had the right combination of time, money, gumption and spousal support. It seems that I've finally got the right combo to make it happen. There are some aspects that I know are out of my league, which is why I've decided to "outsource" the work.

On that note, my wife worked for Randy as his office manager for a year or so in 2010. He's already done the step bars and the grab bar in the cab in exchange for some web design work that I'd done for him. I've kept in touch with him, and he's always been interested in doing the work on converting the 72, and now we've got the chance.

Seeing the work that he's done on a number of other vehicles, I'm in the same boat as you, and really can't wait to see what he's capable. In reference to my other thread, I've got a list of items on my punch sheet, of questions and issues that we will go through when we finalize the scope tomorrow. He's a perfectionist, and I've never seen any sub-standard work come out of his shop. From his 1945 Willy's to his current race buggy, he always ensures that the vehicles are capable.... There's a lot of outstanding things that I'm going to leave to his judgement. (Among this, the front axle & suspension configuration.)

So, I'm going to try and stop by a couple of times, as well as ask him to take pictures of the work, and I'll try to post them up here as I get them.

And, I haven't been this giddy in a while. I first drove a 1971 Chevy K-10 when I was working as a mechanic back in 1989, and knew that I needed to have the 67-72 body style truck. I tried to get my first one when I was in Army training in San Angelo, TX. It wasn't until 1999 that I was able to actually buy the truck... Marriage, two kids, a divorce, another marriage, two additional kids, three jobs and umpteen moves later, I'm finally able to see the finish line on this truck.

Re: Scott's 1972 Chevy K-20. A place to start.
 

So, I was able to finish up a couple of items on Saturday. Finished wiring up the brake controller.

Mounted it under the steering wheel.

https://lh3.googleusercontent.com/-M...o/IMG_0349.jpg

Got the internal wiring all done.

https://lh5.googleusercontent.com/-h...o/IMG_0351.jpg

https://lh4.googleusercontent.com/-n...o/IMG_0352.jpg

And ran all the wires back to the 7-pin connector.

https://lh3.googleusercontent.com/-0...o/IMG_0353.jpg

(Ya, uninspiring look at wires....)

I also fabbed up a quick bracket to run my new halogen light relay's as well as the 40 amp fuse for the positive lead on the positive line.

https://lh6.googleusercontent.com/-8...o/IMG_0354.jpg

Aside from cleaning out the cab and bed of the truck nothing else was done...

Re: Scott's 1972 Chevy K-20. A place to start.
 

So, this morning, I backed out the truck for the last drive as a gas powered beast....

Glory shots of my not so beautiful truck....

https://lh4.googleusercontent.com/-l...o/IMG_0356.jpg

https://lh5.googleusercontent.com/-q...o/IMG_0357.jpg

https://lh4.googleusercontent.com/-i...o/IMG_0358.jpg

https://lh3.googleusercontent.com/HO...=w1105-h829-no

https://lh5.googleusercontent.com/R0...=w1105-h829-no

https://lh6.googleusercontent.com/7o...Y=w622-h829-no

Following in the trailered 1994 Dodge....(no tags, not registered...)
https://lh4.googleusercontent.com/7d...=w1105-h829-no

And we arrived at our final destination...
https://lh3.googleusercontent.com/QV...=w1105-h829-no

https://lh4.googleusercontent.com/sv...=w1105-h829-no

https://lh4.googleusercontent.com/FH...=w1105-h829-no

And, you couldn't find a happier guy right now....

https://lh3.googleusercontent.com/Pr...=w1105-h829-no

Re: Scott's 1972 Chevy K-20. A place to start.
 

Hey, congrats on getting your degree and getting the chance to build a dream truck for your self! If you or Randy have any problems just ask. This is going to be an awesome truck for sure!

Re: Scott's 1972 Chevy K-20. A place to start.
 

Ok, time for questions for which I haven't had the time to figure out answers for.... And, Ryan, since you offered...

I'm looking at fuel tank options at this point. While I understand that custom tanks are all the rage, I've seen a thread that covers a 40 gallon tank from a square body suburban.

In looking at rock auto, they offer the tank for under $200. That, and the 3-outlet fuel sending unit (another $70). The question is (and now that I can't look at the trucks) will this set-up work for the cummins? The P7100 is the pump, so I wouldn't need anything other than an in-line fuel filter, correct?

Re: Scott's 1972 Chevy K-20. A place to start.
 

I actually mocked up a burb tank from an 89 V20 and it fits pretty nicely. What power level would you like to be at later on? On mine I'm going to see if the sending units operate in the same Ohm range. I'm not sure if they're the same from 72 to 89. Either way, I'm ditching the stock suction tube for a draw straw 1/2" diameter. In the past I've simply removed the stock suction tube from sending units, drilled the hole bigger in the sending unit, and brazed a 3/8" line I bent up in the sending unit. You can run 3/8" feed and 5/16" line on your truck and use the factory lift pump on the LH side of the engine block. No filter is needed pre lift pump. There is a screen to filter large debris in the lift pump inlet. You can add one pre lift pump, but you'll want to make sure it can flow what the stock lift pump will flow to not over heat the lift pump. This is another nice feature of an aftermarket fuel system. :lol: But, to keep costs down, you could get a filter head and run a good water seperator pre lift pump and be good to go.

Re: Scott's 1972 Chevy K-20. A place to start.
 

Ok, so from a power level, I'm looking at 600-800 ft.lbs. which should be below 400HP in the 350-375 range. Since I use this mainly for hunting/fishing/camping I usually only pull a small trailer up and back, but most of the time is spent driving around in 4x4. A lot of the places that I go hunting at are 4x4 access in, and don't lend themselves to pulling a large trailer.

Rock Auto states that the sending unit works 0-95 ohm and I believe that the 72 runs at 0-90, so it should be really close. As far as modifications go, I'm hoping that I won't need to modify the pick-up lines and that I'll be able to run without any issues on the 1/2" pick-up tube.

Glad to hear that the mock-up worked well, it is encouraging to hear. I'm sure there will need to be some minor modifications to get the 35" long tank to fit.

Re: Scott's 1972 Chevy K-20. A place to start.
 

I say custom tank!

Re: Scott's 1972 Chevy K-20. A place to start.
 

As my buddies and I frequently joke, it's really easy for you to spend my money.
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Re: Scott's 1972 Chevy K-20. A place to start.
 

it was the cheapest option!

Re: Scott's 1972 Chevy K-20. A place to start.
 

and you are correct, i spend money really well. even better if its not mine

Re: Scott's 1972 Chevy K-20. A place to start.
 

Stock gas GM pick up tube I think is 5/16 maybe 3/8. I know on my 72 it was 3/8, but that fuel injected TBI I think was 5/16. But if it is 3/8", you're good to go. I may have to go custom tank like Ryan mentioned, due to my rear suspension..........................

Re: Scott's 1972 Chevy K-20. A place to start.
 

yeah, that rear suspension is totally hack

Re: Scott's 1972 Chevy K-20. A place to start.
 

Nice one!!

Re: Scott's 1972 Chevy K-20. A place to start.
 

Ok, now that you guys have speculated about GM fuel tanks, allow me to present some facts. The engine supply pipe on V8 GM sending units in this vintage is 3/8. The ohm range is 0-90 on both the '72 and (in this case) up to '91. The 0-95 or 0-100 ohm aftermarket sending units are crap in my opinion. They are inexpensive, but unless you enjoy dropping your fuel tank to change them, I highly don't recommend them. I needed a third one in my Suburban and said screw it and bought the high-dollar GM replacement and my gauge is dead-on now. It wasn't before?? No, it wasn't. The gauge is looking for 90 ohms when full and the sending unit puts out 95 or 100 (depending on whose literature you read--I've seen different numbers from the same company on the same unit (they measured 100 in my testing lab)). The problem with this is, being the gauge is looking for 90 ohms when full and it is seeing 100 ohms, the needle is going to spin way past full and stay there a long time until the fuel level drops to 90 ohm, where it is still going to read full, but you have already used 10% of the fuel in the tank. Is it a problem?? To me, it is. Where I go, I NEED to know how much fuel is in my tank. Not an approximation that is off by 10%. Now, the problems are not just accuracy. One failed when the seal that is supposed to seal the electrical terminal through the top of the sending unit failed because they used Chinese rubber. That created a nice fuel leak. Fuel out, dirt in. Not good. The second one had an electrical failure. Now the third one that I got to replace the second one was bad right out of the box. I hooked my Fluke meter to it before I installed it and it was nowhere near any range that GM ever used. That was it. I ponied up for the GM (gasoline) unit and it is probably the most accurate fuel gauge in my fleet now.

Now, on to the tank. I can somewhat understand the desire to put a new tank in it, but why not get one from a wrecking yard?? We are not in Iowa, and so long as the donor didn't come from somewhere other than here, the worst you would have to do is take it to a radiator shop and have it cleaned. If it comes back ugly, shoot it with a coat of Krylon 1403 Dull Aluminum and it will look brand new. The nice part of doing this is the GM sending unit in it might still work (take an ohm meter with you to check it). Double score for waaaaaaaaaay less than $200 bones for just a tank (I have the GM/Delco part number for the replacement fuel sock on the sending unit if it needs to be replaced). Hell, if nothing else, get the wrecking yard tank and spend the $200 on a GM sending unit. I think that would be more win than a $200 tank and a Chinese sending unit. Also, if you have to (or want to) relocate the fill neck, the radiator shop can do that after they clean it. You can also grab the straps from the donor rig too. These have gone up dramatically in price lately from the dealer.

What tank to use?? I recommend a '73-'86 tank because they were carbureted. The tanks from the '87-'91 trucks have baffles in them that you don't need or want. There is also a difference in fuel fill pipe diameters. I forget exactly when they changed, but this may be a moot point if you are building your own fill pipe setup. Also, another FYI, the sending unit for a 31 gal tank is the same for a 40 gal. So if you find a nice 40 gal tank with a junk sender, but find a good 31 with a good sender swap them out and increase your win for the day.

Just some food for thought.

Re: Scott's 1972 Chevy K-20. A place to start.
 

Excellent write-up, thanks for the insight, and it also explains why my tank has always read over-full in my truck (although I never really thought about it.)

Anyway, I know what you're saying about junkyard parts. I don't mind getting out there to pick them up, but for me, I'm stuck behind a computer for 8-10 hours a day, so it is very easy for me to look up, cross reference, etc. on the computer before I ever get out to the junk yard. Like above, I was able to find a link where someone did the conversion, then find the options of fuel tank sizes for the suburban, and finally get the dimensions so I can go measure things up. Some people do that in a junk yard, I sit behind a computer.

It also gives me a good idea of what I'm willing to spend for a part. If I was ok looking at $500 for a custom welded tank, it makes me think that $300 for an off the shelf tank might be ok, where I need to figure out the mounting, or $100 from a junkyard, and I get to spend the time R&R'ing the part.


Yes, I understand that my computer skills make me fat and slow, but I've got some serious gaming skills in the event that I get to the point where I never want to leave the couch again.

Re: Scott's 1972 Chevy K-20. A place to start.
 

And having hit save before I finished....

This is one that I really was planning on going to a junkyard for. The problem (in this case) with going with the purchase new option is that I'm missing parts. The new order doesn't include the skid plate or any of the fueling neck options, so I'll see what I can do to figure that out. On that note, any personal recommendations on junkyards for american iron around the Phoenix area?

Re: Scott's 1972 Chevy K-20. A place to start.
 

Ok, more research last night, putting my internet searching powers to the test... (and a reference if anyone else can use it.)

Ok, I've been trying to piece together the steering/hydro-boost components.

It looks like the hydro-boost in the Chevy (starting in 82 with their Diesel trucks) is running the same lines as the Dodge. They're all 16mm male to 18mm male O-ring hoses. Dodge started running the hydro-boost in 1997, it wasn't an option in '94. So, I should be able to get the parts to cover from the power steering pump to the hydro-boost (ACDELCO Part # 36352440) and from the hydro-boost to the steering gear (Dodge: ACDELCO Part # 36352340) or (Chevy: ACDELCO Part # 36357640).

In that set-up, I should be able to run the GM hydro-booster (ACDELCO Part # 14PB4147) with a new master cylinder (A-1 CARDONE Part # 101863). I also found power booster brackets to handle the hydro-boost that are custom made for the 67-72 body style.
Captinfab's Power Brake Booster Adapter Bracket
Captinfab's Hydroboost Mounting Plates


The only thing that this leaves out is the power steering box. The 1972 2wd power steering box is listed as a 3/8" input, so the metrics won't work. That being said, I saw that the part number (A-1 CARDONE Part # 275004) covers from 1968-86, and I've seen reference that they all have the same bolt patterns. It looks like they switched over from standard to metric in '81, so pushing it to the 86, and verifying that it's metric should be good. I have read that the pitman arm from the Dodge should work, but can't verify that until I get the steering box in.

With that, I'm hoping it will be a bolt in operation.

Re: Scott's 1972 Chevy K-20. A place to start.
 

Scott, I'd put an 80's style steering box on it and go on. I think GM started the metric fittings in 77 or so. That's what I did on my Longhorn. The 2nd gen dodge pit man arm might fit, but I do not know that for sure. I do know that the 92 dodge pitman arm was different than the 89 chevy on the burb and I had to use the dodge one on the dodge box. These were 4x4 boxes though.

I'd also highly recommend getting one of these boxes if you are spending the money. I've put a couple of these on dodges and they are way nicer than an OE unit. I haven't used one for the chevies becuase they have just came out recently. The only better option are the Redhead boxes, but I don't think they do the pre 88 chevies yet.

http://www.borgeson.com/xcart/catalo...LY-p-1677.html

I see Redhead will do custom box rebuilds though, might be an option for you.

http://redheadsteeringgears.reachloc...563&kw=5016327

Re: Scott's 1972 Chevy K-20. A place to start.
 

Mosesburb, thanks for the tank and sending unit info! Is the sending unit smaller or bigger for the fuel injected tanks? If I can fit it in there, I may just use the burb tank for now. We shall see.

Re: Scott's 1972 Chevy K-20. A place to start.
 

Ok, made a command decision today that I'm going to deal with the fuel tank at a later date. Talked to Randy, and we're just going to plumb up the existing, in-cab tank for the short term. I'm going to follow some of mosesburb's advise and get to a junkyard to search for a Suburban 40-gal tank, since I'm going to need a "bunch-o-stuff" that'll go along with it.