1979 K20 5.3 Swap

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smurfasaur

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1979
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K20
Engine Size
289
About to start on my 85 k10 SWB. Putting 6.0(lq9 with 4l80 and np241 t-case. I ordered a hooker Mtr mounts & hooker trans crossmember for a c10. I had read on a few other forums that it work with a k10 no mods to it. If not I'll send back and build one. Would like to see what you work up for it yours.

Nice that will be a fun truck. I haven’t heard of using that crossmember before but would be r ally interested if it works.

I plan to do a similar crossmember as this guy fabbed, just hopefully it won’t take me a week like he said his took lol
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rpcraft

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Jimmy
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LS 6.0 364 CID
About to start on my 85 k10 SWB. Putting 6.0(lq9 with 4l80 and np241 t-case. I ordered a hooker Mtr mounts & hooker trans crossmember for a c10. I had read on a few other forums that it work with a k10 no mods to it. If not I'll send back and build one. Would like to see what you work up for it yours.


Hooker motor mounts and stuff probably wont put your transmission and tcase in the right spot but you can redrill the holes in the frame for your transmission cross member easy enough. The more difficult part will be getting custom length driveshafts. You'll probably end up needing to shorten the front and lengthen the rear. that being said I would go to a scrap yard and just find the rearaluminum driveshaft out of a Z71 and have that lengthened to the distance you need and install that, because the factory driveshaft won't hold up too well to a lead foot and highway driving.
 

Calvin curry

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1985
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K10
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6.0
I will have to drill new holes in the frame for crossmember. The motor mounts bolt to factor clam shell motor mounts. They are adjustable front and back. I decided to go with the combination for the 3-5 degree slope for driveline angles. They are Similar to the dirty dingo mounts. The overall length of the Ls power train is longer than the 305 with 700r4 trans that is coming out. Custom drive Shafts will be built for sure. The motor is going to be a little more than mild. I have a btr stage 4 truck cam, Ls swap hooker headers, typhoon intake, cold air and will be taking to speed tech locally for a dyno tune. Should be around 500 hp. Factory shaft wouldn’t support that very long at all.
 

rpcraft

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IF they are adjustable you should be ok then. Your 4l80E is a touch longer than the 700R4 but I think its only about 1.5 inches (don't quote me). I saw a poster on facebook the other day that had the trans lengths but of course I can not find it now because I did not save it, lol.
 

smurfasaur

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Well there is a lot of work left to do before my truck can be road worthy, but the goal this weekend was just to fire it up for the first time. Big old fail.
Got the fuel system finished and also plumbed the tranny cooler (don’t sound like big accomplishments but whew I think they are), and tried to start the truck.

First thing I noticed weird is that when I turn the key on the fuel pump doesn’t prime for 3 seconds like it should. Tried starting it and turns out it doesn’t get power at all, and I think actually all the pink wires aren’t getting power with key on. Using a DIY standalone kit from BP automotive and it has provisions for AC and electric fans that I’m not currently using. Thinking that could be my problem.

Also broke my fuel switching valve and then ordered the wrong one [emoji58]. Got a good pollak valve but I need a single wire solenoid type valve because I don’t want to rewire everything to use the pollak valve so I bypassed the valve and hooked up to one tank right now. Got a single wire valve coming.

PS if anyone else is using a Walbro inline pump BE CAREFUL when tightening the ground and power studs. They break easily, don’t ask me how I know.

To do list before **** can be road worthy:

-Get running
-Fab tranny crossmember
-Hook up exhaust headers to existing dual exhaust - cutting ends off the headers and welding in O2 bungs
-Hookup Dakota Digital speedo cable 8k signal generator and converter box that converts to 128k for VSS
-Finish filling tranny with atf
-Fill transfer case with atf
-Bolt seat down
-Bolt seatbelts in
-Get new windshield
-Hook up lokar shift linkage
-New tires to replace the dryrotted bfgs- thinking of either going with 33x12.5” toyo ATs on the stock wheels or 33x12.5” Nitto Ridge Grapplers on Black cragar wheels. About the same price ironically for toyos from Les Schwab with no wheels vs. Nittos from custom offsets with new wheels
-Alignment
-Drill and tap fitting for steam line
-install accessories
-figure out power steering line situation: I bought a high pressure line and a return for a 2003 Tahoe but the pressure line fitting is the wrong thread. Going to try a ‘79 k20 line
-Find a new damn rag joint. Bought a jeep Xj shaft but apparently I either bought the only Cj shaft that doesn’t fit on a square steering box or my steering box is a freak. Also bought a new rag joint but **** doesn’t fit


Not critical to get on the road but probably should do at some point:
-Check brakes
-Check diffs fluids
-Modify tcase shifter - right now binding up for some reason
-Install LED jeep JK headlights and wire to use relays
-Install new vent window gaskets and window rubber stuff
-Wire in a secret ignition cutoff switch. My insurance won’t let me get any coverage on the truck so I figure it would be a cheap insurance policy to protect my $6k investment into this junk
-Install a late model auto dimming compass mirror
-Install Cruise control from late model


Damn that’s a lot. Haven’t put a list together before and I’m sure I’m forgetting some things. I also have a crapload of duplicate parts I need to get rid of. If you need something for an LS swap let me know I have a bunch of random stuff

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roundhouse

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Make sure the trans is filled before you crank it

Running the engine without adequate fluid on the trans can damage the trans
 

smurfasaur

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Make sure the trans is filled before you crank it

Running the engine without adequate fluid on the trans can damage the trans

I put almost two gallons on fluid in it before I cranked it, it was starting to creep up the dipstick so I stopped before I had a mess.

Just giving myself a reminder to go back and fill it up all the way [emoji1360]


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smurfasaur

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Some fresh pics
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rpcraft

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LS 6.0 364 CID
That is kinda the state mine was in yesterday before I started taking stuff off again. I put the battery in to try and roll the windows up (for towing and storage outside) and was praying when I turned the switch on that I would get some action.. No luck. I have a replacement wiring harness i am going to install so I just figured I'll do the windows later once I get it moved with the battery and the power probe and I went ahead and stripped out the old harness and gauges, plus all the garbage under the dash. While under there I decided now is the time to go ahead and drop that assembly that holds the brake pedal and vacuum booster and sand blast it and repaint it.... Needless to say once that is done I got a couple of holes to weld back up on the floor board and then I am going to lizard skin the metal part of the dash, the firewall, and the the tub and sides.
 

smurfasaur

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That is kinda the state mine was in yesterday before I started taking stuff off again. I put the battery in to try and roll the windows up (for towing and storage outside) and was praying when I turned the switch on that I would get some action.. No luck. I have a replacement wiring harness i am going to install so I just figured I'll do the windows later once I get it moved with the battery and the power probe and I went ahead and stripped out the old harness and gauges, plus all the garbage under the dash. While under there I decided now is the time to go ahead and drop that assembly that holds the brake pedal and vacuum booster and sand blast it and repaint it.... Needless to say once that is done I got a couple of holes to weld back up on the floor board and then I am going to lizard skin the metal part of the dash, the firewall, and the the tub and sides.

Damn, sounds like you’re doing a lot more complete job than my hackjob lol my strategy is to get my garbage running and driving and reliable so I can sell my big payment late model duramax and then make it pretty


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rpcraft

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LS 6.0 364 CID
I started with just an LS swap and keep finding more things to fix, lol. My goal originally was to get it going to daily driver status and get rid of my daily driver payment mobile as well, lol.
 

smurfasaur

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I started with just an LS swap and keep finding more things to fix, lol. My goal originally was to get it going to daily driver status and get rid of my daily driver payment mobile as well, lol.

Just gotta lower your standards of what’s acceptable lol I’ve been watching too much roadkill...


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rpcraft

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LS 6.0 364 CID
Funny you mentioned that, I was watching the new episode of RK garage last night and fell asleep searching craigslist with the limit set to 1800 dollars, lol.
 

4WDKC

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That is kinda the state mine was in yesterday before I started taking stuff off again. I put the battery in to try and roll the windows up (for towing and storage outside) and was praying when I turned the switch on that I would get some action.. No luck. I have a replacement wiring harness i am going to install so I just figured I'll do the windows later once I get it moved with the battery and the power probe and I went ahead and stripped out the old harness and gauges, plus all the garbage under the dash. While under there I decided now is the time to go ahead and drop that assembly that holds the brake pedal and vacuum booster and sand blast it and repaint it.... Needless to say once that is done I got a couple of holes to weld back up on the floor board and then I am going to lizard skin the metal part of the dash, the firewall, and the the tub and sides.

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rpcraft

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LS 6.0 364 CID
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Yup, it's OK though. I figure I can do some work with it running (interior stuff) and it's better I do the stuff that is going to prevent it from turning into a rust bucket now, so I can get more enjoyment out of it later down the road.
 

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