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1978 Chevrolet K20 Build and L31R Vortec Engine Swap

Discussion in '4wd Pick-Ups K/V 20 2500 K/V 30 3500' started by chappy78, Dec 7, 2019.

  1. chappy78

    chappy78 Supporting Member Supporting Member

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    First Name:
    chappy78
    Truck Year:
    1978
    Truck Model:
    K20
    Engine Size:
    350
    I've made some good progress preparing my new Chevrolet Performance Vortec 350 L31R (P/N 12681431) for installation. If you haven't read my intro thread, please check out the link below for a little background:

    https://www.gmsquarebody.com/threads/hello-from-seattle-area-1978-chevrolet-k20-intro.27765/

    After a slow start due to a defective engine hoist that delayed me from raising the engine from the crate onto an engine stand, I now have the engine together and ready to go into the truck. (I had a little trouble with the 1 ton Pittsburgh engine hoist from Harbor Freight, which was a low-quality POS. After I spent the time assembling that junk, I discovered the hydraulic ram was defective and wouldn't lift so I returned it and rented an excellent 2 ton hoist from a local rental shop.)

    My first job was to remove the rocker arms, pushrods, lifter guide retainer, lifter guides, lifters, oil pan, front cover, timing gear, and finally the stock camshaft. I used a handy valvetrain organizer from Summit (P/N 900013), which was worth every penny.

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    Using some moly grease I lubricated and then carefully installed the new Chevrolet Performance camshaft (P/N 14097395). This is the same camshaft as used in the burly HT383 stroker motor. I followed the installation instructions to a T, carefully reassembling the valvetrain and adjusting valve lash. This was a satisfying, enjoyable task.

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    I upgraded the stock plastic front cover with an aluminum piece from Holley (P/N 21-151) which deletes the unnecessary (to me) cam position sensor hole. The Holley cover is high-quality part although I wish it had a better timing pointer. After re-installing the hydraulic damper, I installed an MSD cam timing tape (P/N 8985) on the damper and highlighted the pointer notch with a paint pen.

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    It's worth mentioning that you have to remove the oil pan to remove the front cover on these Vortec engines with the one-piece seals. (I didn't enjoy rotating the engine on this engine stand to remove and re-install the oil pan.) I re-used the stock gasket for the oil pan but added a little RTV at the joints between the pan and the front and rear seals. I installed a Chevrolet Performance oil filter adapter (P/N 19299222) with bolt set (P/N ALL92001) from Allstar Performance and a Wix oil filter (P/N 51061). I used the new gasket that Holley supplied to install the front cover and put a spot of RTV to hold the front cover's locating pins in place at their two locations.

    Next I installed the Chevrolet Performance dual plane intake manifold (P/N 12496820), with the Fel-Pro "problem solver" intake manifold gaskets (only sold part of set MS98000-T). These gaskets seem to be the best available and they appear to be of very high quality. They have a metal core and formed rubber around the bolt holes and intake and water passages. I laid a bead of RTV at both ends of the block, overlapping the edge of the gasket with RTV before installing and torquing the intake manifold bolts in two passes. The bolts I used were also from Chevrolet Performance, P/N 12550027. I sealed them with some thread sealer although they appeared to have some factory-applied sealer on them.

    The next day after the RTV set up, I installed the EGR block-off plate (EBay purchase from seller "sevensat", P/N EGR-BOP-SBC-G1), EGR block-off plug (Chevrolet Performance P/N 12556596), and 5/8" heater hose fitting (Dorman P/N 56356). I put the Speedmaster oil priming tool (P/N PCE400-1001) into the distributor opening and installed the distributor hold down clamp (MSD P/N 8110), which is a piece designed to work with my Holley Hyperspark distributor. I also installed the temperature sensor (Classic Industries P/N TU46) for the warning light, as well as the oil pressure sensor (OER P/N 10045707) for the warning light and oil pressure sender (VDO P/N 360-003) for the gauge. I installed the oil pressure sensor and sender on an 1/8" tee from Ebay seller Carchoice17.

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    Next I installed the modified exhaust manifolds (P/N 192X-G) from Brzezinski Racing Products with Fel-Pro gaskets (P/N MS94054) using hardware from Classic Parts. The exhaust bolts (P/Ns 86-033, and 86-034), stainless washers (P/N 86-030), stud (P/N 86-039), stud nut (P/N 86-040) and exhaust bolt locks (P/N EN-2820) all fit great. I used some high-temperature copper anti-seize compound on the bolts and stud.

    The Chevrolet Performance dipstick tube (P/N 12552920) and dipstick (P/N 10190942) went in next. The tube installed simply with a bit of RTV and a 1/4"-20 bolt.

    I used AC Delco Iridium 41-993 spark plugs (P/N 12681665).

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    Tomorrow I'll focus on preparing to remove the engine from the truck by draining the fluids, removing the Sniper EFI and all the accessories from the engine and pull the radiator. I'm planning on removing the core support and pulling the engine out from the front to keep it the lift height as low as possible.

    chappy78
     
    Last edited: Dec 8, 2019
  2. animal

    animal Super Moderator Staff Member

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    Truck Model:
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    Engine Size:
    350ish
    Nice work so far :waytogo:
     
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  3. chappy78

    chappy78 Supporting Member Supporting Member

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    chappy78
    Truck Year:
    1978
    Truck Model:
    K20
    Engine Size:
    350
    I only had a few hours to work on the truck today but I managed to get the engine stripped down and detached from everything except the transmission and engine mounts. The exhaust manifold bolts really fought me and slowed me down quite a bit. Removing the core support is quite a chore but I'm confident I can finish removing it with a couple of hours more work.

    I'm looking forward to getting the engine pulled and having lots of space to work in the engine bay to clean and paint and replace the engine harness and front light harness. My goal is to have the new engine in and at at least connected to the trans and engine mounts by this time next week.

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  4. HotRodPC

    HotRodPC Administrator Staff Member

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    Engine Size:
    454 - Turbo 400 - 3.73 350 - 700R4 - 4.10
    Making it happen !!! :waytogo:
     
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  5. Snoots

    Snoots Supporting Member Supporting Member

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    First Name:
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    Truck Year:
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    Truck Model:
    Jimmy Sierra
    Engine Size:
    350
    Very well written and with PIX!
    The addition of part numbers and POP is GREAT!
     
  6. 75gmck25

    75gmck25 Full Access Member

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    Truck Year:
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    Truck Model:
    K25 Camper Special TH350 NP203
    Engine Size:
    5.7
    To pull my engine I used a borrowed hoist and balancing bar. I used the lifting eyes on the engine, and it looks like yours are still there.

    Once the bolts were out for the bellhousing and motor mounts I could slide the engine forward (hanging from the hoist) and disengage from the transmission. Then we tilted the front of the engine up a little to clear the front crossmember and it came out very easily. I removed the old and installed the new engine with all the accessories bolted on the front of the engine, and with the stock exhaust manifolds still on the engine. IIRC I may have left the metal fan and thermal clutch off until it was in, but I'm not sure.

    Make sure you have space in front and a level floor to wheel the hoist forward and gradually jack up the engine at the same time so you can clear the area around the radiator support.

    Bruce
     
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  7. chappy78

    chappy78 Supporting Member Supporting Member

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    Truck Model:
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    Engine Size:
    350


    Thank you very much for the info, Bruce.

    I finished removing the core support today but I had a setback that I could use a little advice on. One of the bellhousing fasteners stripped when I was trying to loosen it so I am going to have to pull the engine with the bellhousing attached. The bolts between the bellhousing and transmission broke free easily.

    Does anyone know of any issues I will encounter pulling the engine with the bellhousing attached? The clutch will have to slide away from the transmission input shaft so I am anticipating having to pull the engine forward before I can begin the vertical lift but are there any other snags I should plan for?

    Thanks in advance for any advice!

    chappy78

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  8. Camar068

    Camar068 Supporting Member Supporting Member

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    Truck Year:
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    K10/LM7 5.3/4L60e/np208/3.73/31"
    Engine Size:
    10 yrs Air Force
    get a buddy and you can get the fenders n inners, hood, core support and bumpers out of the way. The tires make one hell of a seat when your workin on it....let alone all the shit out the way. Cover with a tarp or 2 when your done at the end of the day if working outside.
     
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  9. chappy78

    chappy78 Supporting Member Supporting Member

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    Engine Size:
    350
    Hi, thanks for your reply. The core support is out and everything is detached except the engine from the transmission and motor mounts. One of the bell housing bolts is stripped so the only option I have is to remove the engine with the bell housing attached.
     
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  10. chappy78

    chappy78 Supporting Member Supporting Member

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    Truck Year:
    1978
    Truck Model:
    K20
    Engine Size:
    350
    Progress report:

    This afternoon I removed the stock engine and it's sitting on a pallet in the garage.

    :cheers:

    A point of note: I couldn't find any definitive answer to a question which I answered for myself today:

    "Can you remove a Chevrolet 350 small block from a 73-87 Chevrolet truck with a SM465 manual transmission without removing the bellhousing?"

    The answer is definitively yes. It's f*&king easy. In fact, I propose this should be the standard process and recommend anyone doing a square body engine swap with a 350 and SM465 should do this instead of trying to separate the engine from the bell-housing. The bellhousing-engine bolts are tough to access and in my experience the heads of those bolts are easy to strip. The SM465 to bellhousing bolts are robust and easy to access. In addition, there's only four transmission-bellhousing bolts versus the six bellhousing-engine bolts.

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    Next steps:

    1. Remove bellhousing from stock engine.
    2. Clean and paint bellhousing.
    3. Install Chevrolet Performance flywheel and Centerforce clutch kit on new engine.
    4. Install new engine wiring harness and front chassis harness into truck.
    5. Install electric fuel pump relay and electric fan relays and wiring harnesses into truck.
    6. Install new motor mounts on frame cross members.
    7. Clean, paint, and install motor mount brackets onto new engine.
    8. Replace SM465 transmission input shaft seal.
    9. Install bellhousing on SM465.
    10. Install new clutch pivot stud, clutch fork, throwout bearing, and clutch fork boot on bellhousing.

    Thanks for reading!
     
  11. chappy78

    chappy78 Supporting Member Supporting Member

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    Truck Model:
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    Engine Size:
    350
    Another day of progress. The engine went in without too much trouble but it was a challenging task to accomplish alone. I have to return the hoist tomorrow so I was under some time pressure to get the job done and I'm pleased with the result of my effort. I didn't have time to clean and paint the firewall, frame, and inner fenders as I would have preferred but I'll have more time to do cosmetic work next summer. I also didn't get to the relays or wiring harness but I'll tackle them as time allows this week.

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    In the photo below you can see the KRC water neck spacer (P/N 15375000) that I used to receive the coolant temperature sensor for the Sniper EFI and the VDO coolant temperature sender (P/N 323-421D) into the two 3/8" NPT ports. I installed the water neck with two nice gaskets (P/N G2399, one each above and below the spacer) from Summit that appear to be manufactured by Mr. Gasket. I've read conflicting information about locating the sensors near the thermostat but I have been happy with the results so far (in my stock engine). Chevrolet Performance specifies a 180 degree thermostat for this engine so I picked up a Motorad Safe-T-Stat P/N SS180-0072 from NAPA to replace the 195 degree unit from the stock engine.

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    In this photo you can see the sensing lugs are below the thermostat and I think they're close enough to the main coolant passages that they're reading accurately. I'm retaining the coolant temperature idiot light in my new dash so I relocated the sender for that to the top of the intake manifold.

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    Thanks for reading!
     
  12. chappy78

    chappy78 Supporting Member Supporting Member

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    Engine Size:
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    After a very busy week at work culminating with a enjoyable and festive work party, I was able to spend some time continuing to re-install the engine accessories and finish the installation of the fuel system, engine wiring harness, fuel pump relay, and electric fan relay.

    I had previously removed all unused input and output wires from my Sniper EFI wire harness so with my new Spal electric fans I needed to re-install the fan output wire. In the 10-pin connector I had removed everything except the white (crank sensor input) and dark brown (tach output). I reinstalled the light blue Output #1 fan signal wire to drive my Spal electric fan wiring harness and integrated the wire into my wiring harness.

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    The Spal relay requires a switched 12V connection so I ran another wire for it to my switched BlueSea terminal bus. That new wire joins with the terminated 12V switched signal from the fuse panel, the Sniper EFI 12V switched signal wire, and the secondary electric fuel pump 12V switched signal wire. (I'm aware of the RFI concerns but I'll address that issue if/when it arises.)

    I finished wiring and plumbing the new secondary electric fuel pump (which I needed since there is no mechanical fuel pump provision on the L31R). This is a Holley / Sniper / NOS unit (P/N 80000100) that flows 96 GPH at 7 psi which will be more than enough to feed my Edelbrock EFI fuel sump.

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    In the picture below you can see (from left to right) the Painless Performance relay for the secondary electric fuel pump, and the the Spal 60A fuse and relay for the electric fans. I connected the relay signal connector for the switched 12V wire and the signal wire from the Sniper EFI unit but I'll wait to connect the fan power wire until I re-install the radiator core support, radiator, and electric fan module. I coiled and stowed the battery feed wire which I'll connect once I've installed the battery tray and battery.

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    You can see the installed water pump (A/C Delco P/N 252595), power steering pump (A/C Delco P/N 36P1435), and alternator (Powermaster P/N 47294) in the picture below. The power steering belt is A/C Delco P/N 15360 and the alternator belt is A/C Delco P/N 15448. I had to slightly modify the power steering pump bracket common to the cylinder head. There appears to be minor geometry differences between the stock small block head mounting holes versus the Vortec heads. I used a round file and elbow grease and solved the issue - the brackets fit perfectly now and the belt lines up nicely. The alternator is upgraded and new to accommodate the extra draw from the new secondary fuel pump and the electric fans but I re-used the power steering pump and water pump over from the stock engine. They were recently replaced and should serve the new motor well for many years.

    It's shocking to see how quickly the raw steel water pump and exhaust manifolds developed surface rust - just two days in the moist PNW air and a few blown drops of rain produced bright orange rust on both.

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    After the holiday this week I'll finish the engine wiring, re-install the Holley Sniper EFI, Hyperspark distributor, MSD plug wires, starter, and prepare to install the radiator core, radiator, and electric fan module.

    Thanks for reading!
     
    Last edited: Dec 24, 2019
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  13. 77 K20

    77 K20 Full Access Member

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    First Name:
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    Truck Year:
    1977
    Truck Model:
    K20 5" lift
    Engine Size:
    HT383 fuel injected
    Out of curiosity are you going to be doing a coolant bypass?

    From the owner's manual:

    "Any small block engine, regardless of year, that uses Vortec heads, will require an external coolant bypass line from the intake manifold to the 5/8" hose nipple on the water pump (passenger’s side). Suggested routing is from the 3/8 NPSF boss on intake manifold to the water pump."
     
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  14. chappy78

    chappy78 Supporting Member Supporting Member

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    Truck Model:
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    Engine Size:
    350
    Yes. I’ll plumb it from the port on the front of intake with a 5/8” tee into the 5/8” supply line to the heater core.
     
    Last edited: Dec 25, 2019
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  15. chappy78

    chappy78 Supporting Member Supporting Member

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    Truck Model:
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    Engine Size:
    350
    A quick update. I was able to finish the engine installation and start the truck this earlier week. I’m pleased with how it runs. I need to adjust the clutch, reassemble the grill and lights, finish the dual exhaust, and I’ll be ready to drive it in a few days. I’m feeling great about this progress.

     
    Last edited: Jan 2, 2020

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