Sullii the 72 GMC 1500

[clay68c10]

Looking good!

[hewittca]

Quick update with the completed firewall paint. I used Automotive Touchup basecoat/clearcoat and the match was pretty close considering all I did was give them the correct paint code. The current goal is to have the engine bay completely clean while retaining the OG patina on the exterior.

[Accelo]

Just wondering if the chrome bumpers and the full wheel covers were added after the purchase? This is the lowest option truck I have even seen. I see someone added a radio.
I was under the impression the 6 cylinder was still the base motor? Must have changed by 1972? I have also read where the GMC's had leaf springs stock and this one has trailing arms. I't more likely the GVW had everything to do with the spring type and nothing to do with a Chev or GMC. A lot I don't know and some of what I thought I knew is wrong.
Love the patina. Should be a blast fixing it up.
Cheers

[hewittca]

Originally Posted by Accelo

Just wondering if the chrome bumpers and the full wheel covers were added after the purchase? This is the lowest option truck I have even seen. I see someone added a radio.
I was under the impression the 6 cylinder was still the base motor? Must have changed by 1972? I have also read where the GMC's had leaf springs stock and this one has trailing arms. I't more likely the GVW had everything to do with the spring type and nothing to do with a Chev or GMC. A lot I don't know and some of what I thought I knew is wrong.
Love the patina. Should be a blast fixing it up.
Cheers

Thank you! Yes, it's definitely a low optioned truck. I believe a few things were added to it over the years including the sport bumpers, full wheel covers, and white top. I have reverted back to the original style "dog dish" hubcaps and white wheels, but I will leave the white top and bumpers because I like the look. As for the engine, as far as I can tell it was an all original 307. I was surprised as well to see this one was a trailing arm truck as I also heard most GMCs were leaf spring. For me, I actually like low optioned simple trucks so this one had to come home with me!

[YBNORML]

Originally Posted by hewittca

Thank you! Yes, it's definitely a low optioned truck. I believe a few things were added to it over the years including the sport bumpers, full wheel covers, and white top. I have reverted back to the original style "dog dish" hubcaps and white wheels, but I will leave the white top and bumpers because I like the look. As for the engine, as far as I can tell it was an all original 307. I was surprised as well to see this one was a trailing arm truck as I also heard most GMCs were leaf spring. For me, I actually like low optioned simple trucks so this one had to come home with me!

Looking awesome


As far as the leaf spring debate goes. I believe that only GMC’s were available with leafs but they were also available with trailing arms. Up here it still seems to be predominantly coil spring. I’ve had about 10 or so 67-72 GMC’s and only 2 were leaf spring trucks.

[hewittca]

Originally Posted by YBNORML

Looking awesome

Thank you!

[hewittca]

I took a big step forward to getting this truck back together. I was able to get the motor mounted for what should be the final time. Since this was the second time installing the motor, there were no surprises. With the front fender on it is clear that I will have to do some clearancing for suspension travel. I won't be running inner fenders at first but eventually plan to add some that allow for a big drop. I also cut the hole for the harness to pass through the firewall. I ended up going with a 2" hole and PN 63595K35 from McMaster-Carr for the grommet. I haven't pulled the harness through yet but it looks like it should work.







With the weight of the motor the truck is close to its final stance. It should drop about 1/2" more in the front when it's fully back together. In its current state the frame is completely level. I was hoping for about a 1" rake when done, so I may need to take 1/2" off the rear blocks. I will wait on that until the truck is complete and I have a chance to put some miles on the springs since they are all still new. It's definitely motivating to get an idea of how the truck will sit!

[Accelo]

I agree great looking exhaust.
Looks like Black Widow Mufflers?
I really like the sound.
Cheers

[hewittca]

Thanks guys. Yeah, I guess I forgot to mention what mufflers I went with! They are Black Widow Venom 250s. I watched videos for so many different mufflers, but it's hard to know for sure what it's going to sound like on your own setup. Black Widows have made a big splash in the muffler world over the last few years so I figured I'd give them a try.

[bigmoe]

One thing I've discovered (and and maybe others can chime in) is the exact same exhaust system on a small block chevy sounds different the newer LS engine.

[regan wilson]

Originally Posted by bigmoe

One thing I've discovered (and and maybe others can chime in) is the exact same exhaust system on a small block chevy sounds different the newer LS engine.

It's the firing order. Your truck is coming along nicely.

[Accelo]

I am using Black Widows on my LS. I like the sound. Your cross over it better done than mine so maybe yours will be different. Not too loud at idle, and just above, but I am not leaving the neighborhood without everyone knowing. No drone at all. I would be lying if I didn't say they are loud with much throttle. The best part is the sound when it starts up and on cold choke. Really a great sound for a cam with only 212/218 duration. Mine smooths out substantially after it warms up.

[hewittca]

Originally Posted by Accelo

I am using Black Widows on my LS. I like the sound. Your cross over it better done than mine so maybe yours will be different. Not too loud at idle, and just above, but I am not leaving the neighborhood without everyone knowing. No drone at all. I would be lying if I didn't say they are loud with much throttle. The best part is the sound when it starts up and on cold choke. Really a great sound for a cam with only 212/218 duration. Mine smooths out substantially after it warms up.

Sweet! Do you have any videos of yours running? I would eventually like to put a cam in mine, but for now it will be a stock '04 5.3.

[Accelo]

No videos but I will attempt to get one I can post.
I am using the BTR Stage II truck cam. I am really happy with it. The LS1 is all stock with the exception of the LS6 intake the cam and headers. Made 354hp at the wheels.
It works with the stock converter. But you will be leaving some acceleration on the table without a converter. Simply put the converter get the motor into its power-band quicker.
Smaller tires with harder compound do the same thing as they spin easily so the motor reves into the power band. However, it just makes the spin worse. It's a balancing act with our trucks. Lack of traction because all the weight is on the front is a huge issue. If you don't have a posi HP becomes an effort in futility. I had a stock 06 Corvette and one just punched it and you will in the low 13's without effort. My LS1 has more engine HP than the LS2 in the Corvette. The C10 the tires are narrower the weight is more and the weight on the tires is less. It is way harder to drive fast. The advertised 0-60 time with the 06 Corvette is 4.6. Best I have been able to do with the C10 is 6.2 seconds.
I have a set of slicks I need to try as traction is such an issue. Especially in the winter.
Rambled enough.
Cheers.

[clay68c10]

Kids and dogs!
The truck is looking good, nice and clean

[CG]

I wish I had the skill set to pull off this kind of a build. I really like how it is all coming together. I thought the bed being shallow would be something I wouldn't care for, but it really isn't bad at all. When you think about it how often do you fill the bed to the brim?

[hewittca]

Originally Posted by CG

I wish I had the skill set to pull off this kind of a build. I really like how it is all coming together. I thought the bed being shallow would be something I wouldn't care for, but it really isn't bad at all. When you think about it how often do you fill the bed to the brim?

Yeah agreed. In this truck, I have the HD rear drop springs, but my hauling capacity is still probably weight limited before volume limited with my drop. My other truck also had a raised bed and for 90% of what I use a truck for it is more than adequate. It definitely makes hauling larger items a little awkward, and limits how much you can fit if you are loading up with something that can utilize the full volume like mulch. Honestly, I found myself wishing I had the extra length of a long bed over the extra volume of a full depth bed!

[KyleSeal]

Really like that you did the firewall in a factory color rather than satin black. Looks awesome!

[hewittca]

The more I look at this motor, the more I realize there are so many little odds and ends required to complete this swap, who knew?! I am making progress, but none of it recently has been terribly exciting. In an effort to stay up to date and provide some useful info for anyone searching for answers in the future I will continue the mundane updates.

A while back when I installed the 302-1 oil pan I didn't think about the dip stick. Recently, I noticed the hole in my engine block and thought something ought to go there. That's when I realized I needed a new dipstick and the original truck one would not work. Apparently a 12625031 tube and 12669528 stick from a later model Camaro will work. I have since confirmed this is correct and it fits nicely around the Summit manifolds. Another thing here that has shown up in previous photos but I failed to mention are the plug wires. I went with original equipment Delphi XS10389 and they are niiice. Lastly, notice the PCV feed line from the manifold. This is stock for the 5.3 and I saved this guy from the junk yard. The return from the PCV on the other side of the manifold is also stock style.



For the steam vent (I may have mentioned this already) I added a 1/8 NPT fitting into the water pump and connected the stock hose directly to it. I decided to keep the line that feeds through the throttle body. I am not hot rodding this engine, so no need to delete this (for now). I will reuse the stock brake booster hose since it has a nice curve formed in it. I also disassembled the fuel rails/injectors and fully tested and rebuilt these with a kit from Amazon. All injectors tested fine w/ some backpressure from a can of carb cleaner and a pulse from a 9V battery. After a cleaning and new o-rings they are good as new. Also spy the ICT Billet purge valve block off. Can't leave any gaping holes in the manifold now can we? Also notice the copper line behind the manifold. I removed the 5.3 oil pressure sensor since apparently it isn't used for anything other than the CEL. I replaced it with an Auto Meter 2268 adapter that let me convert from the M16x1.5 in the block to a 1/8 NPT so I could connect a standard mechanical oil pressure line.

It was about this point that I realized just how unsightly the stock truck manifold is. Originally I was going to leave the Vortec cover off because I think that piece is kind of hideous as well, but if the tradeoff is looking at this manifold, maybe I'll use the cover afterall. I could smooth this intake, but that's a lot of work!



For now, I threw the cover on just so I could stop looking at that intake. I may have to save this dilemma for another time. Right now, I am focused on making this thing run!



Here's another photo for fun. Just an old truck with an old small block. Come to think of it, this "modern" engine is already 20 years old!

[cornerstone]

Originally Posted by hewittca

The more I look at this motor, the more I realize there are so many little odds and ends required to complete this swap, who knew?! I am making progress, but none of it recently has been terribly exciting. In an effort to stay up to date and provide some useful info for anyone searching for answers in the future I will continue the mundane updates.

I for one certainly appreciate the "mundane" updates. I know what you mean though, I bet most of the guys who do this as a hobby are like me, in this way... watching others handle similar hurdles gets me through the boring or monotonous jobs required to build a respectable ride.

It's also good that you're so thorough. I can't tell you how many times when starting a new phase of my build that I'll go back and review my favorite truck builds and remind myself how it should be done before I tear into whatever it is. It's a huge help.

[Accelo]

Just think of the pain you are not having to deal with by going with a manual steering truck.

[hewittca]

Originally Posted by cornerstone

It's also good that you're so thorough. I can't tell you how many times when starting a new phase of my build that I'll go back and review my favorite truck builds and remind myself how it should be done before I tear into whatever it is. It's a huge help.

Yes, I often do that as well! There are quite a few tricks and techniques I've used on this build that I found through other build threads.

Originally Posted by Accelo

Just think of the pain you are not having to deal with by going with a manual steering truck.

That is very true! Hopefully I still like the manual steering as much as I did with the stock suspension. At the very least, I can get it driving as is and upgrade later if I don't like it.

[hewittca]

Here's another round of incremental updates. My photos are all starting to look the same, even to me. I think I should just post the photo and see if anyone spots the differences, like one of those pictures from when we were kids. Circle the differences!



Seriously, if you've been following along, you may have noticed that the wiring harness is installed and all engine side plugs are connected! It took a little finagling to get the harness through the 2" hole I cut in the firewall, but it eventually cooperated. The grommet I found on McMaster worked out as well, although I did end up needing to cut it to get it on the harness. There was no way to force the plugs through it. Ideally, I would have depinned everything and slid the grommet on. You can also just barely see my positive side power feed-through bulkhead thingy on the firewall. This is straight up racecar stuff. My dad works in NASCAR doing wiring and he gave me this. The plan is to run the alternator to this junction point, and then another wire to the starter. More details on this in a later update.



Inside the cab, things are coming together as well. Again, you can just barely see that bulkhead coming through the firewall where I have my LS harness and truck harness power source joined. I am probably going to add a fusible link on the truck side since there was one factory and I lopped it off when rerouting everything. The LS side is fairly well protected by the fuse panel, which you can see to the right. It is easily accessible from below the dash, even after I add a shallow glove box (one day). I also have my PCM mounted up using a GM 15995679 mount. The PCM has been flashed by Brendan at LT1swap.com and should be ready to play nice with my swap configuration. Lastly, note the TAC module for the DBW (thats drive by wire, for those like me who always think, what's that mean!?). I will add more details on the actual pedal later. There are some annoyances associated with that.



For the battery, I decided to move it to the passenger side framerail behind the cab. I had a perfect spot there since my frame is stepped. I wanted to get it off the nose and also clean up the engine bay in the process. Plus, with the air intake needing to occupy that real estate, I had to do something. I got this battery box from Summit (PN SUM-430023) and it turned out to be nice quality.



That's enough wiring for now. Onto something else. While the truck was sitting on the ground at one point I noticed my front brake hoses were very tight, like, guitar string tight. I did a quick search on the forum and found out I'm not the first one to discover this issue on lowered trucks! There were plenty of suggestions, most commonly that C20 front brake hoses would work since they are 2" longer. If you keep digging, it seems most retailers have phased out the real C20 lines and just sell the same part for C10 and C20s. Someone said Brothers has the right C20 lines, so I ordered up a set. Wrong! They were the exact same length as my C10 lines. At one point 67ChevyRedneck posted a nice solution here using Nova/Camaro brake hoses. So, I ordered up a set. Although they do work, they are too long given my drop! They rub quite extensively on the spindle through the range of motion.



At this point, I had to venture out and come up with my own solution. I noticed that if I could just rotate my original line and reclock the banjo fitting I would get some more slack in the hose. The original orientation has the line coming out towards the top. Problem is, there is a nub that locks the banjo fitting in place. I decided to pull the calipers and grind down the lip that clocks the banjo fitting so I could rotate it to exit the caliper more horizontally. On the left is the modified right side caliper, on the right is the original left side caliper. After doing this, it freed up just enough length and now fits perfectly. There is no rubbing or stretching of the hose in any position.







Last up for this edition of random updates is engine/trans fluids. I learned a little something in that GM changed the threads on the oil filter at some point. I mistakenly grabbed a filter for a 2004 Camaro (PF46), thinking the shortie filter would work with my 302-1 muscle car pan on my '04 engine. Turns out I need a PF48 filter, which is from 2007-later Camaros. I don't know why this was changed, but at least now I know what filter I need. So to my future self, you need a PF48 filter. Top it off with about 6 qt of 5w-30 oil and we are SO close to turning this motor over for the first time (since it was swapped).





My NV3500 transmission was also filled up with some GM recommended ACDelco 75W-80 Synchromesh Transmission Fluid. The drain plug had normal metallic sludge on it which was a good sign (no metal shavings!). After about 2.5 qt it was satisfied. My daughter joined me in the garage for this step. This photo was taken at 6 am. The new puppy I mentioned a few weeks ago thinks 4:30 am is a good time to wake up. I am on morning puppy duty on the weekends, so might as well make use of the extra time!



Since I like to always try and include a macroscopic view of the truck in with all these detail shots, here's another photo. Between my last post and this one I have now crossed over the 2 year mark of owning this truck. In that time I have driven it a total of only 30 miles! Definitely was not my original intent with this one, but I'm happy where it is headed nonetheless. Here it is the day I brought it home.

[zicc1835]

I have to thank you for your recent visit to my build as a result I just spent the last 2 hours going back to Green Gus which I visited in 2016 for the first time( I was in my mid sixties at that point )and today I found this new build of yours ...ill say it once again,7 very good years later you are blessed with family and talent ...thanks for sharing good luck on the first drive its around the corner awesome build looking forward to hearing that motor run with that custom exhaust ,.....amazing

[hewittca]

Originally Posted by zicc1835

I have to thank you for your recent visit to my build as a result I just spent the last 2 hours going back to Green Gus which I visited in 2016 for the first time( I was in my mid sixties at that point )and today I found this new build of yours ...ill say it once again,7 very good years later you are blessed with family and talent ...thanks for sharing good luck on the first drive its around the corner awesome build looking forward to hearing that motor run with that custom exhaust ,.....amazing

Thank you! Yes I have been very fortunate. The kids keep me incredibly busy with school and all their extra curricular activities, but it's worth it. I still find time to sneak away to the garage every now and then. I'm looking forward to hearing this thing as well and will definitely post a video once I fire it up. I've not been able to find an example video of a stock 5.3 engine with this exhaust configuration, so hopefully it sounds alright!