1972 K20 LQ4/4L80E Swap

[pilotXC]

Originally Posted by suburban99

A couple of things....on my 72 there is next to no room from the firewall to the valve covers. I can slip a finger in but that's it. I used the dingo sliders and normal clam shell mounts. My turbo 350 is in stock position. The K series are different from the C series...They just don't have the room.

I see on one picture that you have an EGR style passenger exhaust manifold. I would find a 2006? or newer manifold that does not have the egr.

I had no issues with the alternator hitting.

My Saddle tanks have 2 bolts thru the middle (long)...and one on the outside that replaces the tie bar rod that stabilizes the wheel area.

I recommend the Windstar electric fans, there are cheap fit excellent and work good.

Thank you for the details... Happen to have any pictures you're willing to post of the engine in the truck to compare to what I am looking at in mine? I've been going back and forth with DD and they keep saying, "what's the problem, you have tons of room? Why do you want to move it forward more?" Kind of annoying considering these mounts are sold WITH the cross member for a 4wd as an option, you would think there would actually be some use to the 4 inches of adjustment, but there seems to not be at all.

Has anyone used these manifolds? They look like a good option and I like the thin 2 bolt flange for the clearance issues.
https://www.summitracing.com/parts/p...make/chevrolet

I looked at the TBSS manifolds and I'm not convinced they will clear the frame with the wide 3 bolt flange, but the price from GM direct is good, $55 each.

I got my tanks out, had to cut the bolts between the top of the tank and bottom of the bed, they had decades of crap in the holes and I had to pound the crap out of them to get the rods out. Couldn't get them to budge with an air hammer while they were in the truck.

I got a Windstar fan, totally agree that the fit is great, and it was $38 and an hour of my day in the u pull it yard.

Anyone used the Tanks Inc in tank kit? My original plan isn't going to work out...
https://www.summitracing.com/parts/tnk-pa-2

[rowdy11]

I am using a cutout template for my firewall, not my actual cab, but notice even with that I'm going to have the same clearance issue with my K10. I checked the underside and don't have a ton of room to slide forward further without hitting my oil pan against the DD cross member (and I have the truck pan).
Pilot did you say you flipped sides on the mounts and it helped? Was that the engine mounts or the clamshells/crossmember section that you flipped?

[pilotXC]

Originally Posted by rowdy11

I am using a cutout template for my firewall, not my actual cab, but notice even with that I'm going to have the same clearance issue with my K10. I checked the underside and don't have a ton of room to slide forward further without hitting my oil pan against the DD cross member (and I have the truck pan).
Pilot did you say you flipped sides on the mounts and it helped? Was that the engine mounts or the clamshells/crossmember section that you flipped?

I messed around with the mounts more today, flipped them again (the slider part that bolts to the block. I put the "P" on the D side and the "D" on the P side) and it gives a lot more room between the firewall and engine, but you can't adjust it back at all AND the cross member won't go in because the oil pan is too far forward.

Bottom line is there's only 1 way to mount the engine in a K series truck (I think the mounts were engineered for a C series and they "work" for a K series so they haven't bothered to make a better option as I doubt there is enough people doing K series swaps to make it worth the investment and/or not enough people have complained) it seems with the Dirty Dingo clam shell/slider/cross member combo. All the way forward, which puts the engine very far back against the firewall. I'd appreciate a more well engineered piece of $114 metal myself and am pretty disappointed in the motor mounts and the customer service I got. They didn't reply without bothering them and were condescending and dismissive when they did... Happy with the cross member overall, but in retrospect like the look of the Pacific Fab version better.

I have a friend who's a professional fabricator and considered going to him and seeing if he would replicate the DD slide mount but allow for actual adjustment, but I'm kind of in a time crunch to get this knocked out, so will make it work as it is and I think once I get the transmission in the right position, it will be ok.

[pilotXC]

Got the summit brand manifolds and mocked them up today and they clear everything. First thing that actually bolted up and was a done deal. Also got the cross member moved about 3" back and a spacer under the trans adapter roughed in so everything is now bolted down. Started getting the tank ready as well. Couple more weeks and it should be at least able to drive...

[Daaaanz67]

Those manifolds look just like Holley LS swap just without there logo. Subbing

[pilotXC]

Originally Posted by Daaaanz67

Those manifolds look just like Holley LS swap just without there logo. Subbing

Here's the link to the ones I bought. I liked that they had the collector with the O2 bung already in them and the 2 bolt pattern versus the 3 bolt. The bung is 360 degree adjustable also. Didn't really plan on buying new manifolds, but the stock LQ4's didn't fit and I wasn't aware there would be that big of clearance issues when I started this project.

https://www.summitracing.com/parts/sum-g9084?rrec=true

Cleaned up the transmission spacer we made yesterday and painted it today. Rounded up a new front drive line that I'm 99.9% sure will bolt right onto my transfer case output/diff yoke. Just held it up today for a minute and seems like it will work out and clear the cross member, thankfully. One more thing on the short list that doesn't have to be modified... Got a rear drive line and dropped it to get cut down to the right length. Didn't take any photos today to post... Will try to snap a couple tomorrow.

[Daaaanz67]

Man that’s a great deal, I’m actually running the Holley swap manifolds. They didn’t come with the collectors and cost more. Definitely going to keep these in mind for next swap.

[pilotXC]

Final mounting (hopefully) of the transfer case and the transmission mount. I used the stock 2001 GM trans mount and made a spacer. Installed manifolds with O2 sensors, installed water pump and a few other miscellaneous things. Hoping to have the tank close to ready with sender and pump installed tomorrow and possibly get going on the wiring.

[pilotXC]

Worked on the tank today, got the sending unit holes drilled and tapped. The plate steel on the dealer aux tanks is damn thick, so that worked out pretty good. Drilled the holes for the Tanks Inc in tank pump kit, plug welded the attachment ring and assembled the pump kit. A few other things here and there, but that was the main focus.

Need to work on mounting the factory aux filler neck now and sourcing some type of carriage type bolt to re install the gas tank.

[landarts]

PilotXC excellent work on the truck, following along and getting ready myself to do my first LS swap into a K10. Thanks for the documentation. Again nice work!

[Duck1]

Originally Posted by pilotXC

I'm finally getting going on the actual swap part, hope to have some pictures soon...

Anyone know a powersteering pump/reservoir that fits with the stock bracket that only has 1 return line? I tried a Tahoe version and it doesn't work...

Just swap the whole fitting from your old pump to the Tahoe tank

[pilotXC]

Originally Posted by Duck1

Just swap the whole fitting from your old pump to the Tahoe tank

The return line is in the way of rear bracket on mine, it didn't work. I just capped the extra return line.

[pilotXC]

Finally got the tank done. It took a ton of work to get it to where it is. Had to relocate the filler neck, add a vent and weld closed the old filler neck hole. Chased leaks for a while as well... Not pretty, but it's done. Not to mention adding in a sending unit and the Tanks Inc EFI in tank pump kit. Also found a way to use new carriage bolts to hold the tank in. Got some threaded bolt connectors with a tapered allen head for the bottom side of the tank so it's lower profile. Drilled out some fender washers and welded the carriage bolt head to it and trimmed off the sides so it will fit between the corrugated bed metal. Also cut the hole in the bed for the factory aux tank location and closed up the aluminum dealer filler tank doors.

I know the location of the aux tank is not ideal, but I don't like the idea of the tank in the suburban location. I haven't seen one that doesn't hang too low for my liking. I also read retrofitting the stock behind the seat tank isn't easy and I wanted to room behind the seat if possible. I don't drive the truck a ton, and understand the risks, but options are limited so I made a educated decision to go with the driver side tank...

[pilotXC]

Couple pictures of the retro fitting of the factory auxiliary tank filler neck. The one I found was the same color as my truck, and about the same "patina" (rust). I use my truck to haul my motorcycles, to haul stuff for my house, etc. so not looking for a trailer queen. Just want a nice reliable truck, it's not the most pretty, but it is a great truck when it's running and driving!

[pilotXC]

I've been horrible at snapping pictures as I go lately and with the holidays was more tied up with family obligations that I expected and didn't get a ton of time on the truck.

The harness is in, tank is installed, plumbed, and wiring ran to the engine bay.
Throttle cable from Lokar installed, pretty cool part, well made and pretty easy to do.
All the little things are sorted, temp gauge adapter, oil pressure (I drilled and tapped the LQ4 one that many do, pretty easy, but would have been easier by a lot when the engine was out), torque converter bolted to the flex plate and tranny dust cover on, brake booster fitting and new longer hose to the booster, found the right size hoses (I think) for the filler neck, and I'm sure I'm forgetting other odds and ends, but my long list is nearly done and I have the wiring of the LS harness to do, install the core support, radiator and hoses and fill it with fluids and I should be ready to start it. Maybe, just maybe, I'll get to do so by end of week!?!?

Finally also got the Windstar fan and shroud all done with brackets and spacers, etc. Turned out pretty good. Gonna be tight on the hoses, but should be ok. Mine is wired as a 1 speed 2 fan set up from the donor van, but has the 2 speed motor on the big fan. Gonna try to find the right pig tail for that and wire up a 3 relay circuit for 2 low speed fans and 2 high speed fans. I think it will work great! Only picture I got for now...

[suburban99]

Originally Posted by pilotXC

I've been horrible at snapping pictures as I go lately and with the holidays was more tied up with family obligations that I expected and didn't get a ton of time on the truck.

The harness is in, tank is installed, plumbed, and wiring ran to the engine bay.
Throttle cable from Lokar installed, pretty cool part, well made and pretty easy to do.
All the little things are sorted, temp gauge adapter, oil pressure (I drilled and tapped the LQ4 one that many do, pretty easy, but would have been easier by a lot when the engine was out), torque converter bolted to the flex plate and tranny dust cover on, brake booster fitting and new longer hose to the booster, found the right size hoses (I think) for the filler neck, and I'm sure I'm forgetting other odds and ends, but my long list is nearly done and I have the wiring of the LS harness to do, install the core support, radiator and hoses and fill it with fluids and I should be ready to start it. Maybe, just maybe, I'll get to do so by end of week!?!?

Finally also got the Windstar fan and shroud all done with brackets and spacers, etc. Turned out pretty good. Gonna be tight on the hoses, but should be ok. Mine is wired as a 1 speed 2 fan set up from the donor van, but has the 2 speed motor on the big fan. Gonna try to find the right pig tail for that and wire up a 3 relay circuit for 2 low speed fans and 2 high speed fans. I think it will work great! Only picture I got for now...

Good progress! Make sure engine is filled with coolant from top rad hose as these LS’s are difficult to get air out..
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[pilotXC]

Here are a few pictures with the air cleaner, throttle cable, and of the oil pressure sending unit re-installed after being drilled and tapped. I have a few more wiring things to finish up and getting the core support fully re-installed, radiator in, fill with fluids and then should be good to start. Was hoping I'd be there last week, now I'm hoping I'll be there this week, but also have some things tying me up until Wednesday before I can get to it again. Hoping by next week it will be 100% "done." It's never done, but at least back driving and usable...

[pilotXC]

Originally Posted by WS7z

So excited to see someone else doing a K20 with a 4l80 swap! Im about 2 years into mine and will be taking my time in between work and raising 5 kids. Look forward to updates and to see where you finally mount the engine. The 4l80 is something like 6 inches longer than the previous setup that you removed. Im curious how you will handle the drive lines as that is something I am not fully clear how to solve yet.

best wishes on the build.

Quick update for you on the drivelines... I went to the yard I got my engine at a while back and grabbed a slip yoke rear drive line for $40. They didn't a front to work with the NP208 yoke the right length, so I went to another spot down the road they recommended. He had a couple the right length so I picked one up for $75. Ouch after spending $40 on the rear! Dropped off the rear to get shortened and new u joints. I got a call from the drive line shop about a week later and he said, I think this is already the length you need, can you measure the output shaft on the transfer case? I did, and he said, yeah, you are good with this as is.
Long story long, I got 2 drivelines I didn't have to modify at all to fit directly in the truck. I believe they are Suburban shafts. I can provide any measurements you might need for my set up, just let me know. Was nice to just bolt something on for a change as well!

[pilotXC]

I'm SOOOO bad at photo documenting this project! I'm trying to get as much done in short amounts of time and just don't think about it as my wife is about to pop with our 2nd and 3rd kids and our 2.5 year old son is still napping and needs a lot of my time given my wife is about to have 2 kids and can't help as much as usual... All that said, I got everything back together on the front end except the grill and bumper. Radiator, fan/shroud are installed. PCM is mounted on the driver inner fender and I have a couple fuses and grounds to do and loom the wiring and all the under hood wiring should be pretty much done. A few odds and ends on the under side to finish up (connect trans cooler lines, connect battery and ignition wires to starter), bolt in drive shafts and exhaust (not sure if I'm going to try to do it myself or bring it to a shop) and that's more/less it. Still need to hook up the tach to the PCM also under the dash, but can do that whenever, just want to get it driving again so I can bring it home if needed! Aside from that, need to do the cosmetic stuff that came with eliminating the stock cab mounted tank and the passenger side aux tank, sanding and some paint blending in those areas. Hoping I'm damn near done, or close, by end of the week. I got 2 weeks to finish it before I start a new job as well, so time crunch is on now... I'll try to take some more photo's tomorrow!

[pilotXC]

IT"S ALIVE!!!!!

Started it up yesterday and I was expecting some issues and had, seemingly, zero. After getting all fluids in, I primed the fuel system, checked for fuel at the rail and from there with my stomach in knots I crossed my fingers and turned the key to start... Cranked 3-4 times and fired right up!!! I hadn't done coolant because I wasn't sure what was going to happen and didn't want to drain it all again if I had some issue, so ran it for about 1 minute and shut it down. Checked all the fluids, oil, trans, etc. Did a few other odds and ends.

Today I got all the coolant hoses connected, filled the engine first with coolant, then the radiator, connected it all up. Finished the 1 wire I still had left on the Windstar fans (I wired the big fan to come on as the fan 1 and small fan as fan 2, both fans should be on with fan 2 signal). After I got all that done I started it up again, fired up right away, and ran it up to operating temp monitoring gauges. Here's the checklist:

Oil Pressure - Yep, looked good and went up when I gave it a little gas.
Temp - Yep, started to go up after idling for a bit and stayed about where it was on the old 350, slightly lower on the gauge.
Battery Charging - Yep, ran a volt meter across the battery and had 14.4 volts when it was running, 12.2 when it was not.
Fans - Ran it until the fan 1 kicked on, just to make sure it worked, and it did, worked like a charm! Came on for maybe a minute, then turned off again.
Coolant level - kept the cap off while it ran to monitor level and kept adding fluid as it went down. Finished with just over 4 gallons of fluid in the system total. 2 of dex-cool and 2.25-ish of distilled water, including the overflow.

****AMMETER**** - YES, it works just fine actually as it should!!! I did a lot of research, thinking, asking questions, etc. (thank you VetteVet) and it still works! I LOVE having factory gauges and am so stoked this works! I'll post a wiring diagram when I have a few minutes to sketch it out if anyone else is interested. Again, thanks VetteVet, he gave me the initial diagram and I modified it a bit from there. I just didn't believe all the posts and comments I got from literally everywhere saying, just disconnect it, it won't work with the LS harness and the CS130 alternator. Where there is a will, there is a way!

I'm sure I'm forgetting so many things on what I did and I planned to post all the details and specifics of each hurdle and how I solved it with part numbers as I found it so hard to find everything is one place. I'll try to go back to do that for reference.

I still need exhaust from the manifolds back to the mufflers, put in drivelines, hook up the tach, and transfer case linkage, as well as body work and a little paint, but it feels SOOOOOO good to know it runs and that there seems to not be any issues!!

[mongocanfly]

Great..!!!!!!!

[Richard]

Build looks great. Congratulations on getting it running. I have to ask is there any rubber or urethane in your trans/transfercase mount? If it is a hard mount I would be a bit worried something would break due to twist if motor is not hard mounted as well. Have seen transmission cases and adapters break just due to the side mount used on some 205's. That is why GM eliminated it on later models.

[pilotXC]

Yes, I used a stock 2001 Suburban (I assume it's used on other vehicles across many years) transmission mount bolted to a spacer for the right angle to the differential. I also used the original transfer case side mount from the NP205 with the rubber bushings, had to modify where it bolted to the transfer case, so there is no hard mount on anything...

[pilotXC]

Here's the wiring on the alternator/ammeter.

[pilotXC]

Started getting into the final stage, body work... Here's a couple before-ish (after filling the aux fill door panels and removing the cab lights) shots. Try to ignore the lift in the way of the truck.

I removed the bed rail caps, not a fan of diamond plate and just don't like it. There were a ton of holes drilled on the bed rail, so welded those up. Also have always wanted to get rid of the cab lights since I got it, just don't like the big after market ones personally. Glad I did, they were wired by twisting the wire together and taping it! And there was some rust under them, so good to clean it up.