My 1970 GMC resto-mod, 4 years of changes...

[Extended Power]

Thought it was about time I tried to document all the work I have done to my wife, and I’s truck over the last four years.
It all started with me regretting the fact I sold my old 1969 GMC over twenty years ago, and could not find it again, to see if the owner would sell it back to me.
After showing my wife a bunch of fixer uppers, she finally lost it and said, “Why do you always show me trucks that are basket cases, and never done?”
And with that comment, all I did was scroll a couple more pages on Kijiji, and found the one we own now.

Here it is after I drove it home from the car wash after leaving the previous owner’s house.

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Things the previous owner SAID it had:

427ci engine with a turbo 400 transmission. (454 crank in the stock 402 block)
4.11:1 posi rear end.
Ceramic coated exhaust.
Brand new brakes all around.

Turns out, some of those were lies.
As far as the engine, who knows...I sold it after driving the truck for two years without having any rumpity rumpity rump. It couldn’t pull a greasy sausage off a plate it was so gutless. Any higher than 4K rpm and it just flattened out completely.

The rear ended turned out to be a 3.08 open diff.

The exhaust...spray paint.

The brakes....well...have a look at the pictures.

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Changes started right away.
I took the time to polish the Centerline wheels, but really didn’t like the 265/60 on all four corners. (On 10” wide wheels)
The truck sat too high...
I didn’t like the mirrors at all.
I had to get rid of the carb.
Battery was old and crusty.
Shocks were worn out.
Interior was icky with the white panels, and worn out...everything. Just look at that seat!

She needed a really good cleaning.

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More interior pix.
Didn’t care for the screws holding the temperature controller together.
Notice some changes already...new pedal covers.

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Started ordering lotsa stuff.
It was ridiculous for awhile.

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More stuff and changes:

[cj847]

I recently did my rear brakes. The drums said max dia 11.08". I measured them with a tape measure at between 11 5/8 and 11 3/4". The shoes looked similar as well.

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Also changed the radiator, heater core, heater housing, all the trim pieces inside the cab changed from white to black, bumper guards added, as well as side window louvers.

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Refinished the bed floor...

[Shifty One]

Originally Posted by Extended Power

It couldn’t pull a greasy sausage off a plate it was so gutless.

I'll be using that one quite a bit, thank you very much...

[dagnabbitt]

Truck looks really straight. Good bones for what you want to do with it.

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At some point, I wanted to swap from 6 bolt to 5 bolt...which also lead to finding out the rear gear set was 3.08:1.
I had ordered a 3.73 gearset as it would rev to the moon when I drove it home...and thinking it was 4.11's, the change to 3.73 gears would slow it down more along with the taller tires.
So new Moser axles were ordered for the 5 bolt pattern.
New Outlaw II wheels were bought just to have wheels with the correct bolt pattern, and were cheap, while still looking good.
Also bought the complete front crossmember off a 72 so I could have the disc brakes, and 5 bolt pattern...
Which lead to 3" lowered A-arms, and pulling out 3 leafs out of the back spring packs to drop the rear.
And added Cal-Tracs when I swapped the open carrier to a new Tru-Trac with 3:73 gears.

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More pix:
Tinted the back window, new tailgate trim.

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So...after it was lowered, the side mirrors were really starting to bug me.
Not sure what the last owner was shooting for, but I think he missed the mark all together.
Maybe if the truck was a factory color, and factory ride height, etc....but not now...
So I started looking for a mirror that would look really good.
And after awhile I found the perfect match for the truck.

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So after the truck was lowered, the side mirrors were really starting to bug me.
So, I had to start looking around for a sporty looking mirror that would go with the look of the truck.
And I found them.
The big issue now, was to get them color matched, and have the holes in the doors fixed.

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Other stuff changed were the flooring.
I went with what I thought was supposed to be a quality product...TMI, but when the carpet showed up, and after the install...I have nothing good to say about their 3 piece crap-et.
After one summer, I had to pull it all out, and went with ACC.

Had to remove all the old insulation that was glued to the floor,and then put Dynamat down.

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Swapped the head unit that was in the truck for one that had Blu tooth.
Went old school on the system.
Alpine 3539 amp for the two 8" Bazooka tube subs.
Alpine 3539 amp for the 6.5 mids.
Alpine 3537 amp for the Alpine tweeters.
Added a Helix DSP Pro.

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Other additions:
Line lock
Moser diff cover
New door latches which are polished stainless steel.
Door seals (Honda)
Ring Brother's hood supports

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Enjoyed driving the truck for like one summer after all that work.
Really missed the fact that the engine ran smooth, and didn’t have a lumpy cam.
Came up with a plan....but it was gonna be expensive.

Found a used GM 572/620 for sale that was four hours away from me.
When they wife gave me the “ok” to buy it, I wasn’t gonna wait and ask again to be sure I heard her correctly.

Enter the 572:

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The engine was used....”Very little run time.” Was a quote from the previous owner.
Being that it was on a pallet, there was no way of hearing it run, or even spin it over to see if it had any type of damage.
So the VERY next day, I’m out in the shop...and the wife walks out and asks me, “What the F@%k are you doin?!”

I said, “I’m not going through all the work of installing this engine without inspecting it first.”

So I tore it right down.
Now, as I mentioned before...I can’t leave anything stock for very long....hence my motto: “If it ain’t broke...fix it ‘till it is.”

I sent the block out to be honed, even though there was still lots of crosshatch in the cylinders.
I sold the GM aluminum heads, and bought AFR 335v2.
I changed from the GM hydraulic roller cam, to a Straub Technology solid roller, solid Morel lifters, Straub Tech roller rockers (Harland Sharp), Smith Brothers 7/16” chromoly pushrods, stud girdle, new double roller timing chain, cam button, and all the quirks and issues of using a gen 4 roller valve train in a gen 6.
Lots of measurements, and fitting.....
All new coated bearings, ARP head studs, main studs, cam bearings...you name it, it was changed.
Ordered a set of custom Lemon’s Headers, and was told to take the new oil pan I just bought back, and “get this one....it will give you clearance for the oil filter.”

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All this happened in a matter of a couple years.
Bought the truck on November 4th, 2019, and was at the point of disassembling the 572 on June 10, 2021.
Took a long time to get the cam and other parts due to the pandemic. (Covid)
8 months for just the cam and lifters.
In the time I was waiting for block machining to be done, and parts to come in, I found a stock GMC tailgate for....drumroll please!

$50!!!!

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Now I said earlier that I bought the Outlaw II wheels just to get the truck driving again because of the bolt pattern change....
I also wanted to pick a new, not seen on every other '67 to 72 truck out there wheel.
And after talking to Schott wheels, I had some made up, and after they came in, I had the rear end narrowed to accommodate them with the new rubber!
I also took that time as an opportunity to get rid of the C clips, and added big Ford bearing ends.
With narrowing the rear end, I now needed to get wider wheel wells too.

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I was not happy with the way the bed floor turned out.
The epoxy was wavey in a few spots, and I wanted it perfect.
So I sent Frank at Smokey Road Rod Shop an email, told him exactly what I had, and he built a new floor for our truck.

Also had the original GMC tailgate redone at the same time the wider fenderwells were done.
Just a note here...there are some autobody companies who will try to take advantage of you if you let them.

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Now this brings us up to the last year and a half.
This is where I pulled the old engine out, and placed the new 572 in the engine bay.
It was so tight, the passenger side valve cover hit the heater box housing.
Fine...who needs a heater...
Pulled it off, and made a cover for the holes.
Then I found a brand new Vintage Air gen iv AC unit for our truck!!! (Facebook market place)
So then I had to remove the cover I just made, to install the cover that VA included in their kit.
I also had to move the engine forward another inch or so, to have enough clearance to pull the passenger valve cover.
Engine was too tall from adding the valve cover extension piece to gain clearance for the stud girdle.
And since this new engine has between 750-800hp, I new there was no room or way, that a brake boost was ever going to work...so...hydroboost was added. (Another score from marketplace)
And just when I was finishing hooking up the adaptive things for using the stock temperature controller, I found a brand new Dakota Digital DDC-4000...once again, on market place. The guy was only asking $250 and I was really wondering why it was so cheap...like...missing parts?
Nope, he said he had been trying to sell it for like 6 months, and had zero interest...he just wanted it gone.
No problem! I'll take it!!!!

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Common issue with hydroboost is not having enough volume...and since the power steering pump reservoir that was on the engine I bought had a broken fitting, I opted to buy a detached reservoir from PSP.
I also didn't want to take a chance on not having enough fuel for the new engine, as the FITech 1200 only flows 950cfm, I bought a Gen 3 Holley 1150 Dominator and Aeromotive 2 stage regulator to knock the pressure down from 60+ psi down to 7.
Another issue with moving the engine forward and having the serpentine belt drive system, was now I had no room to run the dual 16" fans...
I had to find slimmer fans, which I did.