Slo-Touring '72 C20 Suburban daily driver

[FLYNAVY53]

Hey guys, Ive been lurking for a while, learning a lot, and thought Id post the progress Ive made on my daily driver. This started last May when I decided to sell my '06 F250 in favor of something older and cooler. The fiancé was on board, as long as it had 4 doors, sat 4 grown adults comfortably, and had room for our 90 lb German Shepherd, "Chevy". Initially, I was thinking Chevelle wagon, but while cruising Auto Trader, I stumbled on what looked to be a very clean, 1972 C20 Suburban out in rural Kentucky. I contact the dealership, and a deal was struck. Initially, I thought the odometer reading of 34,xxx miles had probably rolled over once, but as I inspected the truck and found the original shocks, zero rust, the original paint with the red primer showing through some spots in the engine bay, and even factory grease pencil marks, this thing may in fact have 34,xxx original miles on it. According to the dealership, they had taken it as downpayment on a new truck 7-8 years ago, and it had sat in the back of their warehouse since then. Either way, for just south of 10K, I think it was a fair deal.

After driving her all summer, including a trip from Norfolk VA to Maine and back for a friend's wedding, I decided o upgrade the running gear on a budget while keeping everything else as factory as possible, to make her a more dependable, and functional daily driver.

The Plan:
LS motor built from Craigslist/Ebay/Junk yard
4L60E from Craigslist
Excessively big aluminum radiator with electric fans
Vintage A/C
Painless Wiring Harness
1" lowering springs all the way around w/ new shocks
Rear disc brake conversion

As she sat the day she was deliverd:
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[FLYNAVY53]

Parts Collection:

https://static1.pt-content.com/images/noimg.gif

I initially purchased a used 5.3L off craigslist, along with a rebuilt 4L60E and torque converter that a local guy had planned to use on a C10 conversion that stalled. After tearing apart the 5.3L, I found that it was actually a 4.8L. Fortunately, I found another guy locally who wanted to build a 4.8 for boost to throw in his Nissan 240. I traded him the complete 4.8L for a 5.7L LS1 short block that he had just pulled apart to inspect and installed new rings. I then found a set of 243 heads that I sent to AI to have cleaned up, with new springs, seats, and retainers, and milled to 61cc chambers along with a 216/224 585/585 112 cam.

https://static1.pt-content.com/images/noimg.gif

Holley accessory drive installed
https://static1.pt-content.com/images/noimg.gif

Crank snout adapter needed to mate older 4L60E to LS motor
https://static1.pt-content.com/images/noimg.gif

https://static1.pt-content.com/images/noimg.gif

[FLYNAVY53]

We're also doing all of this in a one car garage under our apartment....
https://static1.pt-content.com/images/noimg.gif

HUGE help.....
https://static1.pt-content.com/images/noimg.gif

Almost there....
https://static1.pt-content.com/images/noimg.gif

And she's out!
https://static1.pt-content.com/images/noimg.gif

The new CPP tubular motor mounts. For anyone doing the swap on a 1972 3/4 ton, be advised, they came with a one year only motor mount. Because of this, and the different arrangement of holes in the front crossmember, these are the only mounts that I found would work. Because of this, I was also very limited in header selection.
https://static1.pt-content.com/images/noimg.gif

Exhaust carnage...this will be replaced with the Flowmaster, universal C10 set up...have yet to decide whether I want to run the pipes out the back, or turn them out in front of the rear wheels, or behind the rear wheels.
https://static1.pt-content.com/images/noimg.gif

She fought us a bit, but in the end, it wasn't too painful....we did have to flip the mounts on the block around to move the engine an inch further to the rear so that the Holley muscle car oil pan would clear the cross member.
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[FLYNAVY53]

BMP muscle rods cross member
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

I thought this was odd....
https://static1.pt-content.com/images/noimg.gif

Started working on the fuel system. Im running a mallory pump with a 6AN pressure line, up to a return regulator on the fire wall and a 4AN return line back to the tank. The carb is a Holley 650 double pumper.
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

Also started plumbing the cooling system. Im using an Entropy Radiators unit with dual electric fans.
https://static1.pt-content.com/images/noimg.gif
Fan relay mounted behind the batter for easy access but an uncluttered appearance once everything is installed.
https://static1.pt-content.com/images/noimg.gif
Trans cooler lines routed and attached with the overflow tank mounted
https://static1.pt-content.com/images/noimg.gif

Power steering hooked up to factory box. The wheel well had to be clearanced slightly to accommodate the 90 degree fittings on the braided lines. I got the lines and fittings from DSE.
https://static1.pt-content.com/images/noimg.gif

Vintage AC system run and MSD box mounted
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

Remotely mounted the coils low and out of the way to clean up the engine bay a bit. The wires are all tucked up inside the frame rail to prevent them from getting damaged. The MSD cut to fit wires are a little pricey, but worth it I think. Im going to need to get some "cool sox" for the wire boots due to their proximity to the headers.
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif
https://static1.pt-content.com/images/noimg.gif

[FLYNAVY53]

And that is where the truck sat as of DEC 2013 when I headed out for a 6 month deployment to South Korea. I should be headed home next week and look forward to getting her back on the road this summer. The list of little things to finish up is long, with the big hurdle being the Painless Wiring harness, but Im hoping to have it ready to make this drive to Texas this September for my wedding. Items remaining include:

Painless wiring harness
FAST trans controller - wire and mount in glove box
Throttle cable and linkage
Catch can/valve cover breather
Run exhaust system
Shorten factory driveshaft 1" w/ new U joints and yolk for 4L60E
Rear disc brake conversion
Lowering springs - height to be determined (just took 2-300 lbs off the nose)
Column mounted Sun Pro tachometer
Install vintage audio sound head unit and speakers
Potentially incorporate factory rear A/C unit into vintage A/C system
Obnoxious chrome foot gas pedal
Learn to tune a carb

[silvermonte]

Pretty cool project, and a pretty clean body to start with.

[FLYNAVY53]

Thanks! I realize this really isn't the standard "Pro Touring" build, but I do plan on lowering it a bit, adding some beefed up roll bars and maybe hit the local auto-cross....just to see how many cones I can actually kill. I was looking for some aftermarket wheels, unfortunately, the options in 8 lug are fairly limited, so what I found is a set of 16x8 inch steelies from a Ford Econoliner that are the same as factory, but an inch wider. Ill keep the fronts at 16x8 with the factory hub caps and may send the rears out to get widened....theres plenty of room and I should be able to get a 275 or 285 tire back there with the wheel widened to 9.5 inches. I may also have them painted or powder coated black to mute the "ice cream truck" look a bit.

https://static1.pt-content.com/images/noimg.gif

[Gordz32]

Really cool truck man, and your doing a very nice job. I've thought of doing the same thing but I've gotta finish one project b4 the next. I look forward to seeing this finished

[apocalight]

Hey man this build looks great! Looks like a fantastic start and great progress.

A few things to note:

1. Not that you have indicated you plan on racing it ever, but if you did, just be aware that you'd have to move the fuel pressure regulator at least 6" from the firewall (I believe). Don't think they like fuel components to be mounted to it.

2. I'd be a bit cautious about dumping the exhaust in front of the rear tire. If you ever have excessive blow-by or a very rich mixture you could be hosing your tires with a nice, albeit very thin coating of stuff that could reduce traction.

The headers and engine look awesome. So many options/so much potential with those motors.

Looking forward to watching the progress.

[Bob in St. Louis]

Awesome choice in vehicles, I love that body style. Looking forward to the progress.

[FLYNAVY53]

Thanks for the info! Realistically this thing isn't going to see the track, but if its a safety issue (which I could understand) it could be easily moved off the firewall. As for the exhaust, Im leaning more towards turning it out right behind the rear tires...Ill have to take a look once I get back to working on it next week.


Hey man this build looks great! Looks like a fantastic start and great progress.

A few things to note:

1. Not that you have indicated you plan on racing it ever, but if you did, just be aware that you'd have to move the fuel pressure regulator at least 6" from the firewall (I believe). Don't think they like fuel components to be mounted to it.

2. I'd be a bit cautious about dumping the exhaust in front of the rear tire. If you ever have excessive blow-by or a very rich mixture you could be hosing your tires with a nice, albeit very thin coating of stuff that could reduce traction.

The headers and engine look awesome. So many options/so much potential with those motors.

Looking forward to watching the progress.

[srh3trinity]

How do you like the Entropy radiator? I had looked at those.

[FLYNAVY53]

Very pleased with the Entropy radiator! Ill take some more pics when I get home. The model I bought was specifically designed for the LS swap into a C10 or C20. This meant that all of the connections are on the correct sides, and theres even a port for the steam line from the cylinder heads so that you don't have to tap your water pump like Ive seen guys do. As you can see in the picture, the fans and shroud cover 90% of the surface area so it should be pretty efficient. It also has an integrated trans cooler which I liked. Im sure if you were doing serious track events, you would want a better, stand alone unit, but for my purposes, this should be plenty. The only modification required was that I had to trim the rubber isolators that go in the mounts on both the top and bottom. With the new radiator, they were a bit thick.....easy work with the dremel. If you're doing an LS swap, this is definitely the way to go. I can't comment on their other units, but I do plan on using one in my '69 Corvette that is going to retain its SBC so we'll see how well that works out.


How do you like the Entropy radiator? I had looked at those.

[FLYNAVY53]

A few updates from the first week back....albeit, nothing terribly exciting.....

Vintage AC install complete and wiring done
https://static1.pt-content.com/images/noimg.gif

Fan controller wired along with the vintage AC harness, Fast EZ TCU harness, and MSD harness run to the front for those components requiring direct connection to the battery
https://static1.pt-content.com/images/noimg.gif

Wiring out of the firewall grommet. All wiring will eventually be covered in the black braided sheathing.
https://static1.pt-content.com/images/noimg.gif

Also mounted the box that converts the electric speedometer output of the 4L60E into a mechanical signal for the factory speedometer....Im trying to keep the interior as factory looking as possible. Additionally, the box was far cheaper than new gages.
https://static1.pt-content.com/images/noimg.gif

EZ TCU trans computer mounted in the new glove box....the plastic shroud came with the vintage AC unit which is mounted behind. Eventually, this will also house a toggle switch to disable the fuel pump as an added security measure.
https://static1.pt-content.com/images/noimg.gif

Also got the aftermarket stereo head unit installed. Its not wired yet, but I needed it in the dash so that I could start running wires, and eventually install the HVAC controls that go right below it. I have Hidden front and rear speakers, in addition to a small amp and sub for under the rear seat. Should be a nice system without going crazy, and keeping everything out of sight.
https://static1.pt-content.com/images/noimg.gif

[Bob in St. Louis]

That's awesome man. I love that body style.
Thanks for the photos!

[MCMLXIX]

Thanks! I realize this really isn't the standard "Pro Touring" build, but I do plan on lowering it a bit, adding some beefed up roll bars and maybe hit the local auto-cross....just to see how many cones I can actually kill. I was looking for some aftermarket wheels, unfortunately, the options in 8 lug are fairly limited, so what I found is a set of 16x8 inch steelies from a Ford Econoliner that are the same as factory, but an inch wider. Ill keep the fronts at 16x8 with the factory hub caps and may send the rears out to get widened....theres plenty of room and I should be able to get a 275 or 285 tire back there with the wheel widened to 9.5 inches. I may also have them painted or powder coated black to mute the "ice cream truck" look a bit.

https://static1.pt-content.com/images/noimg.gif

Hummer H2 wheels will fit and came with a 315 tire.... just a little tall for what you're doing... but a cheap way to get a 17" rim....

97607

[Destructo]

Any updates? Were you able to take it to the wedding?

[FLYNAVY53]

Oh man....this has been a mad thrash of ass pain! I got her running (however briefly) in early August. Trouble shot numerous problems including a leaking oil pressure gage, leaking coolant lines, etc. After getting that all buttoned up, I took it for a drive around the block, only to find that both rear wheel cylinders were crap.....no time like the present for the rear disc conversion. 2 weeks of scouring the world for the 2-year only rear wheel studs and the brakes were back together. About that time, the ported LS6 oil pump I had used failed in the bypass position which just bypassed oil back to the intake of the pump...unfortunately the engine was running for about ten minutes before I noticed as I was outside the truck checking for leaks. I changed out the oil pump, in the car, which is no easy feat in the LS1, and finally got everything buttoned back up. I brought the truck to the local hot rod shop this week to get the exhaust all welded up. The owner called today to let me know that while the exhaust was on, and sounded great, now that its not running through open headers, he can hear a definite knock coming from the bottom end of the motor. Im going over first thing in the morning to take a look, but it sounds like a spun rod bearing....likely due to running without oil for ten minutes. All that and we're leaving this Friday for the drive to Austin for the wedding. So instead of cruising around Austin for a week, and driving away from the wedding in a cool, old school Suburban, Im driving cross country with a fiancé, all of her crap, and a 90lb German Shepard in a mini-cooper. Needless to say, Im not pleased.

[FLYNAVY53]

Yup, definitely the #1 rod bearing....we put it on the lift and broke out the stethoscope....not good. Im looking into 6.0L LQ9 short block replacements....just what I didn't want to spend money one

[brawls43]

Bummer man. Have had similar problems with other engines in my past. Truck looks awesome though!

[Bob in St. Louis]

Oh dude. My heart goes out to you. That's some good ol fashion crap-house luck right there.

[cali-life]

hey where did you get the black trans line at? cant find any

[driveit]

That really sux. I had a similar issue with a gen 1 engine in my chevelle. I thought I was gonna be able to reuse the crank, but it was really bad. I think I could have had it ground, but I ended with a new engine instead. Well almost new. It had only 8000 miles on it. Don't give up on it though as much as it stinks right now maybe it will work out for the better for you some how. Ever thought of doing a rendering of the Suburban. I have never done a suburban and would like to. I am up for it if you ever decide you want one.

God bless and good luck.

[Auto Rod Technologies]

Wow... Cool find... Nice build as well!!

[DJW32]

The spun bearing sucks.

The truck is a great looking project.

Out of curiosity, did you change the front coil springs when you swapped the motor?

[FLYNAVY53]

Sooooo.....this is where I sat as of Friday afternoon......
103178
103177

The only up side is that this is on the way:
103179

Its a Thompson Motorsports 440hp LQ9
GM 6.0 long block including:
King Racing main/rod bearings
Durabond cam bearings
Mahle Forged Pistons (10.5:1 Compression ratio)
TMS high performance ring set
Chamfered and polished crankshaft
GM floated connecting rods
GM LS 317 heads milled to 67ccs
TMS Billet custom ground camshaft .578 .587 226 232 112+4
Pac 1218 valve springs good to .600" lift
Chromoly pushrods
Melling select high pressure oil pump
GM MLS head gaskets
GM rocker arms and pedistols
TMS 12 point head studs
LS7 high rev lifters
LS2 Timing set
LS2 Lifter treys
Professional assembly
12 month warranty standard

Typically Im not one to throw cash at a problem, but at this point, Im gone for my wedding for two weeks, home for two weeks, then gone for another four weeks in FL for a training exercise which will roll right into the holidays. So I decided to bite the bullet and pay for the long block, and had it shipped to the shop that was doing the exhaust work. They're a local hot rod shop with a good reputation and years of experience putting LS motors into older iron....the owner has a '63 Corvette with a tube chassis and an LS3....I just want this thing back on the road in time to make the drive to Thanksgiving in Ohio and Im realistically not going to have the time to do it myself before the holidays are over.

On the plus side, I'm planning on holding on to the LS1 aluminum block, disassembling it, and eventually sending it out to have the short block rebuilt as a forged 383 for my '69 Vette that will eventually also get the LS swap, ride tech suspension, big breaks, etc...but thats a ways down the road.

Oh well....we made it 26 hours in a mini cooper to Austin TX, so Ill just enjoy myself for the next two weeks, and try not to think about the credit card bill awaiting my return :banghead:

[FLYNAVY53]

not yet....waiting to drive it for a few weeks before I decide what direction I want to go with the springs. I did change the shocks out because the ride sucked and I think it may still have been riding on the originals.
The spun bearing sucks.

The truck is a great looking project.

Out of curiosity, did you change the front coil springs when you swapped the motor?

[FLYNAVY53]

hey where did you get the black trans line at? cant find any

I made the transmission cooler lines with AN fittings and Summit Racing's braided lines....theyre rubber with a braided stainless core and a nylon braided outer for abrasion resistance. They're far easier to work with than full stainless braided lines.

[FLYNAVY53]

Small and frustrating update...the shop got the motor in the truck and running but it "developed" an oil leak. They said it was coming from between the engine and trans so I went over to the shop to take a look...sure enough, they didn't square the rear cover before swapping the oil pan so the main seal in the rear pan was tweaked and gushing oil. Proof positive that if you want something done right the first time, you have to do it yourself. Oh well, hopefully Ill have the truck back and all buttoned up on Monday.

[FRENCHBLUE72]

Good choice on the three door sorry to hear about the motor issues..

[Nicks67GTO]

Nice build. I love those old Suburbans...sorry to hear about the oil pump luck.

[FLYNAVY53]

So.....obviously its been a while.... The cliffs notes version is that I got the 6.0L installed and have about 10K miles on the truck since the build. That has included numerous road trips and one blown 4L60E in the mountains of West Virginia....I limped it home on only 1st and 3rd gear. Following that miscue last fall, I installed a Gear Star 4L65E STGII and haven't had any real problems since. That being said, this past winter I finally got fed up with the cold start issues with the carb, and my wife's inability to comprehend the ritual required to start a cab'd engine after the overnight temps dipped into the teens. So today, I started the upgrade to Holley's self learning terminator EFI and transmission controller. I was never completely satisfied with the MSD box / FAST TCU combo. While the truck ran well at WOT, it always seemed that it wasn't quite right in traffic around town. Either the gear was too high for the speed, or part throttle response was awful, etc....so Im hoping having the EFI, combined with the same ECU running the ignition, fuel, and trans will help with the drivability. Anyway, this morning consisted of mostly removing the old wiring and fuel system. Ill get some pics as I start to install the new fuel system and wiring harness. Ill also post as much info as I can about how the system performs. Ive seen a lot of reviews of this system by magazines that are being paid to say good things, but haven't seen too many real world experiences, so hopefully this will provide some insight for others. Stay tuned!

[Gordz32]

Any updates on your burban?

[FLYNAVY53]

Oh man......so apparently life happens!! A few road trips, many miles, and one deployment later.....

Since my last update, the major changes to the truck have been a complete gutting of the brake system. The only component left is the pedal itself. Unfortunately I failed to take many pics, but I now have a Baer master cylinder, all new fabricated stainless lines with braided stainless flex lines at the calipers, and Wilwood D52 calipers at all 4 corners. I had to go up to 17" American Racing Baja wheels to clear the calipers. I really wanted to keep the factory steelies with the dog dish hub caps, but the drastic improvement t in braking justified the bump in wheel size. The Bajas don't look bad, they're just not as stock looking as I'd prefer. Anyway, please enjoy the below pics of our adventures in the truck.

During our travels in the old Suburban, I stumbled on my dream car....more to come in a separate build thread, but the model year is 1964 and the color is Daytona Blue.....

152883152884152881152882

[FLYNAVY53]

152885152887152888152889152886\

[Bob in St. Louis]

Wow, that is a SWEET truck!!!!!