New Member and new owner of a 1976 K20

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Grit dog

Full Access Member
Joined
May 18, 2020
Posts
6,388
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Location
Auburn, Washington
First Name
Todd
Truck Year
1986, 1977
Truck Model
K20, C10
Engine Size
454, 350
Wow! That truck is gonna be stunning! Nice work!
 

BearKing

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Joined
Apr 13, 2022
Posts
377
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724
Location
Black Hills
First Name
Bear
Truck Year
1976
Truck Model
K10
Engine Size
400
Very nice sir. What a beautiful thing it is turning into. I’m jealous.
 

mtbadbob

Full Access Member
Joined
May 9, 2021
Posts
634
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963
Location
Montana
First Name
Bob
Truck Year
1987
Truck Model
V20
Engine Size
350
The engine:
Ok, so I already mentioned I found an original 400. Since I'm in California, I need to build it and meet the heavy duty emissions requirements. So, I need to keep the smog pump, air tubes, and PCV valve. No cats and no EGR were on the heavy duty emissions for 1976 K20.

Modifications:
* CARB compliant Edelbrock 1400 (600CFM) carburetor
* AFR 195 street heads (I splurged. These look like jewelry). I hated to paint them, but I'm going for an OE look.
* Edelbrock performer manifold (CARB compliant)
* Mellings roller cam/lifters (with specs similar to CARB compliant cam)
* Eagle rotating assembly (crank, 5.7 rods, hypereutectic pistons, etc..)
* Hedman CARB compliant headers with air tubes.
* While the truck had A/C, it was in terrible shape. Rather than try to piece that back together, I went with Vintage Air, so I mounted the compressor in the stock location.

All done and ready to go. On the engine stand waiting to be installed.
Nice truck! My uncle bought a '77 K20 new that had the SB 400. I wasn't overly impressed with it until I bought a '76 Monte with one stock. It was one of the best Chevy engines I ever owned! I've always liked the '79 & up boxes w/fuel access doors the best also. Nice work, she's gonna be super-nice when you get 'er done!
 

mtbadbob

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Joined
May 9, 2021
Posts
634
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963
Location
Montana
First Name
Bob
Truck Year
1987
Truck Model
V20
Engine Size
350
The transmission/t-case:
Of course, the original set up was the TH350 with the NP203. I'm looking to make this a good driver and don't plan to tow anything heavy or any heavy off-roading, so I really wanted to get the RPMs down on the freeway. I choose to go with a TH700-R4 transmission from Gearstar. I went with their Level 3, just to make it as stout as practical. To make life a bit easier, I sent them the t-case and had them rebuild it while they were building the transmission. They mated the two back together and shipped them as a unit on a crate, ready to install. I do need to work through the mounting of the 4WD gear selector, since it is moved back 2". I need to create some spacers to put it back in the original location. Not a big deal, just a little fab work. Note, I'm very impressed with their work. It took them forever to complete it, but not a big deal in my case and they had good reasons (we were in a pandemic after all).
I'm not sure why GM chose to throw the TH350's at the HD trucks. I'm sure you won't be doing any serious off-roading or heavy-duty towing, but I've just seen too many TH350's fail in those bigger trucks. Hopefully it'll treat you right!
 

legend57

Supporting Member
Supporting Member
Joined
Jan 11, 2022
Posts
44
Reaction score
90
Location
San Jose, CA
First Name
Rob
Truck Year
1976
Truck Model
K20
Engine Size
400
I'm not sure why GM chose to throw the TH350's at the HD trucks. I'm sure you won't be doing any serious off-roading or heavy-duty towing, but I've just seen too many TH350's fail in those bigger trucks. Hopefully it'll treat you right!
I think you were referring to the 700R4(?). Yea, I know they are definitely on the delicate side. My personal experience with a 700R4 behind a 400SB has been pretty good for about 20 years in my '57 Chevy. I know its a different beast, but I sure love that overdrive. I'll just have to always keep in mind to treat it nice. Hopefully, Gearstar has done all they can to make it robust.
 

mtbadbob

Full Access Member
Joined
May 9, 2021
Posts
634
Reaction score
963
Location
Montana
First Name
Bob
Truck Year
1987
Truck Model
V20
Engine Size
350
I think you were referring to the 700R4(?). Yea, I know they are definitely on the delicate side. My personal experience with a 700R4 behind a 400SB has been pretty good for about 20 years in my '57 Chevy. I know its a different beast, but I sure love that overdrive. I'll just have to always keep in mind to treat it nice. Hopefully, Gearstar has done all they can to make it robust.
No, the TH350's in the HD 4x4 trucks & Suburban's. They're a great tranny otherwise, but there is a reason they made the tougher TH400. That's just my experience here in the mountains of Montana.
 

oldretiredafguy

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Apr 20, 2020
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1,415
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3,212
Location
N. Texas
First Name
Mike
Truck Year
1988, 1988, 1991, 1983
Truck Model
GMC V-Jimmy, GMC Suburban 4WD, GMC Suburban 4WD, GMC-2500 CrewCab
Engine Size
350, 350, 350, 350
Welcome from N. Texas~!~

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The weather is sure great in your area for doing all the work (or most of it) outdoors. Hopefully, you don't have a HOA breathing down your neck.
 

Maknwine

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Joined
Nov 24, 2016
Posts
101
Reaction score
141
Location
Virginia
First Name
Tom
Truck Year
1987
Truck Model
c30
Engine Size
5.7
Captured this last summer at WM. Seemed nearly perfect to me and that green interior was awesome shape and look. Has the 400 engine emblem and 2 tone green so maybe some inspiration to OP's build...not that he looks like he needs any!

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legend57

Supporting Member
Supporting Member
Joined
Jan 11, 2022
Posts
44
Reaction score
90
Location
San Jose, CA
First Name
Rob
Truck Year
1976
Truck Model
K20
Engine Size
400
Inspiration indeed! Thanks for the pic. That is really close to what it'll be like. The light green along the middle will be white, but otherwise, that's it!
 

Kurnacopia

Full Access Member
Joined
Jan 19, 2021
Posts
259
Reaction score
268
Location
Tucson, AZ
First Name
Mike
Truck Year
1978
Truck Model
Scottsdale
Engine Size
383
Welcome from Tucson, AZ......cant wait to see pics!
 

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