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#1 |
Registered User
Join Date: Feb 2021
Location: WestCentral MN,
Posts: 38
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LS Engine - 1968 4-speed?
My search didn't produce what I wanted... Has anyone here mated an LS engine to their original manual tranny? I have a 1968 C20 with the heavy duty 3-speed+ granny low transmission. Is this possible? My donor vehicle is a 2003 silverado 4x4 5.3LS1 My initial plan would be to convert the LS to a carburetor.
The C20 has only 35K original miles. Bought new by my great uncle but, the motor has sat too long in storage and needs valve work and a new carb. To turn this into a parts chaser and cruiser would be the goal. I came across the 03 silverado cheap... |
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#2 |
Senior Member
![]() Join Date: Sep 2002
Location: Alamogordo, NM
Posts: 711
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Re: LS Engine - 1968 4-speed?
Did a quick online search, "ls1 4 speed". Didn't read it, but try this:
https://www.motortrend.com/how-to/ma...eed-ls-engine/
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1966 C10 Custom Cab Restomod (Sold) 1969 Camaro Z/28 (Keeper) Current Build: 1968 C10 (Semi-Factory Restoration) 1983 Camaro Z/28 (Next in line, Keeper) 1951 3100 (2nd in line) |
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#3 |
Registered User
Join Date: Jan 2011
Location: Chattanooga, TN
Posts: 2,151
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Re: LS Engine - 1968 4-speed?
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'83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project |
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#4 |
Registered User
Join Date: Feb 2021
Location: WestCentral MN,
Posts: 38
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Re: LS Engine - 1968 4-speed?
Thanks, I've read a bunch of that now and have a better understanding in general.
I was hoping someone here had done this on a C20 specifically and kept the existing manual trans. I'll check back each day for updates. |
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#5 |
All about them K’s
![]() Join Date: Jun 2014
Location: Land of Entrapment
Posts: 6,393
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Re: LS Engine - 1968 4-speed?
It’s not that hard. Early 2000’s 3/4 and 1 tons came with a manual transmission. If memory serves me right, You use the flywheel and pilot from one of them. A factory style clutch from your truck should bolt to that flywheel. On the transmission you will omit one bellhousing bolt hole that doesn’t line up. Doesn’t matter if it’s in a c/10, or a c40. The process for mounting the engine to the trans is the same. The easiest thing is to mount the engine to the frame where it lands once it’s attached to the transmission, as the transmission is the fixed point of everything. The 4 speed in your ‘68 should most likely be an SM465. It’s been a while since I looked into doing this with my 6.0 but this thread should help you out better than my years old recollection.
Rather than the pivot ball linkage I’d suggest a hydraulic clutch. That’s the one of the best things I’ve done to my 72. Heres a little more reading… http://67-72chevytrucks.com/vboard/s...d.php?t=421258
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Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's Last edited by 57taskforce; 07-09-2024 at 06:33 PM. |
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#6 |
Senior Member
![]() Join Date: Feb 2022
Location: Ca
Posts: 511
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Re: LS Engine - 1968 4-speed?
I did a LS to Jerico (Think 1970s Muncie Case)
I used a Quicktime Bell housing about 15 yrs ago. The new number is RM-6036. Lots of options as far as TO bearings as it has drilled mount holes or you can float on the input shaft. It was for road racing. This is a SFI certified part so a bit pricey. Likely softer material versions out there. Took a bit of messing with to get the right pilot bearing and flywheel/clutch I wanted. But they were only 7 inches and spun up and down nearly instantly. Clutchless shifting was instant but if you flubbed the rev match it sure went bang. |
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#7 | |
All about them K’s
![]() Join Date: Jun 2014
Location: Land of Entrapment
Posts: 6,393
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Re: LS Engine - 1968 4-speed?
Quote:
__________________
Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's |
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#8 |
Senior Member
![]() Join Date: Feb 2022
Location: Ca
Posts: 511
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Re: LS Engine - 1968 4-speed?
Jerico will not play well on the street. Synchros are replaced with a very large ring with 6 tabs about the size of your thumb. Shifting is done by lifting the go pedal while applying pressure on the shift handle in the direction of next up gear. The release of engine torque on the dog rings unhooks the rings and just that fast you are in the next gear and back on the throttle. Ok for track but on the street you can't drive aggressive enough all the time to correctly shift. If you are a master at rev match maybe. Try driving with out using your clutch. If you can do it full time on the street only clutching at a stop, then you may be able to make a Jerico work driving around town. These in the photo are nicked up and in the junk pile. They don't look bad but it doesn't take much for them to act up.
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#9 |
Senior Member
![]() Join Date: Jul 2015
Location: Warrenton VA
Posts: 1,053
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Re: LS Engine - 1968 4-speed?
As mentioned you'll need to sort out how your clutch will operate as the LS engine won't have provisions for the clutch linkage. I think there are companies that make adapters to work around this, but I would upgrade to a hydraulic clutch. Everything else is "straightforward"
__________________
71 c-10 Long Bed, under the knife for a No Limit Engineering Wide Ride Chassis Pack and coil over static drop. 07 Silverado Classic 2wd 95 Camaro 427SBC/TH350 |
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#10 | |
Registered User
Join Date: Feb 2021
Location: WestCentral MN,
Posts: 38
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Re: LS Engine - 1968 4-speed?
Quote:
Thank you! Another great read. |
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#11 | |
All about them K’s
![]() Join Date: Jun 2014
Location: Land of Entrapment
Posts: 6,393
|
Re: LS Engine - 1968 4-speed?
Quote:
__________________
Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's |
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#12 |
All about them K’s
![]() Join Date: Jun 2014
Location: Land of Entrapment
Posts: 6,393
|
Re: LS Engine - 1968 4-speed?
No problem. I’ll look thru my bookmarks when I have some more time, I bet I have a few more similar threads.
__________________
Tyler '57 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=813888 '72 K20 Cheyenne: 5” lift, 35’s, front dana 60 blah blah blah… http://67-72chevytrucks.com/vboard/s...d.php?t=662879 ‘69 K10 SWB: 4” lift 33”s… in a million pieces http://67-72chevytrucks.com/vboard/s...d.php?t=805206 '98 Silverado LT K2500HD ECLB Vortec 454/4l80E: 6" lift 315/75/16's |
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#13 |
Registered User
Join Date: Jun 2015
Location: Carlos MN
Posts: 2,051
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Re: LS Engine - 1968 4-speed?
Don't know if this helps but I fabbed the mechanical linkage for my 73 Camaro with a LS/TKO 600 swap. Used 3/8" rod ends and tubing. Had about $50 in parts.
See pic. |
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