5.3 LS TKO 600 Swap 87 C10

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atvjoey

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1987
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GMC r15
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Hey guys, I'm undertaking a big project on my first square body and that is to pull the 350TBI with a Muncie m20 in it and put in a mild 5.3 with a TKO 600 AND retain the stock mechanical clutch linkage (I know 87 comes with hydraulics but this truck is a frankentruck). For anybody that's interested, I'm going to be posting up my journey doing this swap here and I've already got a bunch of parts. My question is has anybody ever done this swap before? I haven't seen anybody do it before but it seems straightforward enough. Any information that people can give me would be much appreciated since I'm still trying to figure out how to do it. The biggest problems I've run into so far are getting the LS mated to the TKO properly given the 0.4in difference in crank flange length as opposed to a sbc. The solution I've found is to buy the McLeod extended flywheel and pilot bearing (part #'s MCL-460535, MCL-8617 respectively). People say the Sachs 1050 is the same flywheel and cheaper but I have yet to find anybody that has one in stock anywhere online so the McLeod is the only solution I believe. I'm doing a refresh of my junkyard 5.3 and I just rebuilt my TKO so the swap will most likely happen after the new year but any information you guys have would be great. Thanks again!
 

AuroraGirl

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I have no idea what a TKO 600 is but unless that clutch pivot is somewhere other than stock for an early 80s truck and that happens to line up perfectly where a 5.3 and tko 600 puts the engine or bellhousing where the pivot will work there... I think you better unfranken your truck to a hydraulic because that is some high end luck no one gets lol!

Your truck probably has hydro pedals and the setup was probably not one that needs the hardest to find parts buit instead the wear or conversion parts.
Where does your 350 and m20 place the clutch z bar stuff at? can you show us with pics where and what it looks like there? and then if you show us the pedals someone prob can spot if its hydro pedals still!
 

atvjoey

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They are manual linkage pedals but the z bar frame bracket was homemade so the geometry is off slightly (at least that's what I am attributing it to). I am using the stock truck bellhousing with the bearing retainer adapter to properly support the Muncie transmission so all of the linkage is basically factory except for the weird frame bracket and just being very old & worn out. I might have some pictures floating around but I can't find any atm. I believe since the factory linkage uses the z bar stud on the bellhousing instead of the block that I should be able to keep the clutch fork and just swap clutch kits for the different spline count. I will also be using a Holley Terminator X system to run the LS since I despise the factory ecu and wiring associated with it, plus I would love to learn how to tune my cars.
 

AuroraGirl

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If you want to use the z bar that is fine But my only recommendation is to make sure your z bar is long term gonna be fine and the alignment with the stuff to the pedal and rod are all properly moving so you dont have a bind or break from something unexpected. also, is the trans you want going to place it in the same spot?
 

atvjoey

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Yeah it's going to be in the same place, it uses a stock chevy bellhousing so it should be at least pretty damn close. The only thing I'm thinking about is the LS motor mounts are adjustable forward and backward so I have to line them up properly.
 

LateOnTheBrakes

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I use the sachs on my 5.3 with the SM 465. I got mine at AutoZone. It has worked fine. Don't know about the TKO though I thought that was a mustang transmission. I thought that was a mustang transmission.
 

atvjoey

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I use the sachs on my 5.3 with the SM 465. I got mine at AutoZone. It has worked fine. Don't know about the TKO though I thought that was a mustang transmission. I thought that was a mustang transmission.
do you have a link to the flywheel on AutoZone? I have yet to find anybody that has it but maybe I'm not looking in the right place. Are you using the stock mechanical clutch linkage? any modifications needed to make the linkage work? Thanks
 

LateOnTheBrakes

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Mine has the external slave cylinder on the hydraulic setup.
 

LateOnTheBrakes

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do you have a link to the flywheel on AutoZone? I have yet to find anybody that has it but maybe I'm not looking in the right place. Are you using the stock mechanical clutch linkage? any modifications needed to make the linkage work? Thanks
I bought mine in May of last year. It may be a matter of supply chain shortages at this point.
 

atvjoey

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Update for anybody watching the thread:

So far I have about 90% of the parts for the swap. I just have to finish putting the engine back together and then install all my parts to mate the tko 600 to the 5.3. I should note that the whole point of this build is to be the most fun daily driver. The goals are to get decent gas mileage (~20ish mpg highway on 87 Octane), be able to tow/haul, and get into the 12.XX 1/4 mile range (with the help of some nitrous). I'm doing a simple engine build of a 5.3 LM7 with BTR's newest Truck Norris Cam, better valve springs, full bolt-ons (long tubes, TB, CAI), and a custom tune from a local race shop on my terminator x system which is coming in shortly. I'm using dirty dingo squarebody engine mounts and I'm attempting to retain my amazon cross-member I'm currently using for my m20 muncie. Other than that I need to get the driveshaft cut/remade and redo the rear end so instead of an open 2.73 with 0.64 overdrive ill have 3.55 OR 3.73 posi. I should be doing this swap sometime in late January if all goes according to plan and my parts get here when they're supposed to.
 

atvjoey

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For anyone still with me on this build thread, this is possible. I'm not going to say easy... but possible. I cheated and used a hydraulic clutch since my manual linkage turned out to be hanging together by hopes and dreams and I actually pushed the actuator rod through the clutch fork while I was driving. Needless to say, for anyone doing this swap, it is hard and the money I thought I would save by using the TKO 600 instead of the T56 turned out to be non-existent. T56 would have been a much better option and honestly, the money I spent on the custom flywheel, pilot bearing, and other parts to do the swap did not outweigh selling my TKO and buying a t56. Its also a way more common swap so there are more parts available and information on the web to help you out with your build.
 
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