Ugh, another LS swap


I got a whole lot done today (including the last ride with the original LS1) and took a lot of pictures. Those updates will come later but for now I just want to keep a log of what I have started disassembling; once the reassembly comes, I’ll use it as a guide to see if I forget anything when it’s going back together :slight_smile:

This list starts with a running, driving car

Drained coolant
Drained oil
Removed wheels
Removed axle back, disconnected vacuum lines to cutouts
Removed midpipes, unplugged and de-routed downstream O2 sensors
Unplugged and derouted primary O2 sensors.
*Note, standard off the shelf white zip ties were really brittle due to longtube header
heat and snapped with little effort. Need higher temp solution to secure wiring

Disconnected left rear outer frame ground point (10mm), rear large harness on pass. side wheel well
Disconnect large 10 pin connector on rear passenger side of tunnel
Disconnected rear wheel speed sensors
Removed zillion tunnel plate bolts and plate itself. Thank God for power tools
Rear upper control arm bolts removed
Parking brake brackets removed
Rear brake lines removed and plugged to prevent fluid loss. Normally not necessary but I’ll be upgrading to stainless lines when it all goes back together.
Rear lower shock bolts removed

4x brake line 10mm brackets removed
Front upper control arms removed, attention to washer/shim location
Front brake hoses removed and plugged, etc.
Disconnect pigtail that loops under front sway bar

I need to buy a 12 point socket to install the pushrods and rockers tomorrow, then the new motor is nearly done. Now it’s beer time.


I made a Google docs spreadsheet for my swap. One tab for wiring, one for disassembly sequence (with socket size and torque), one with part list with prices and links, etc etc. It’s really nice having everything in one place that I can access from wherever


Nice. I have been using Google Keep for the planning phase of parts to purchase, just gotta not be lazy and do the same for this.

Rockers and pushrods are all in and torqued down, it turns out I did have the socket for the special 12 point bolts. Just need to paint the valve covers and get them on.

Today’s garage progress:
Unplugged oil temp and oil level sender harnesses
Unplugged clutch quick disconnect line with the goofy little tool.
I was going to go for the starter next, but the longtubes are just too bulky, so they’ll have to come out (or at least move)
Up top: Coil harnesses disconnected, spark plug wires removed, coil pack assemblies removed. Wife did all this. shes the best.
Coolant temp sensor unplugged, clutch remote bleeder removed from mounts to frame
Alternator harness unplugged and positive line removed.
Main serpentine belt and alternator removed.

IAT and MAF unplugged
TPS and throttle body harness unplugged
Intake snorkel and filter assy removed. Throttle body left on car
8x injector harnesses removed (wife again, what a surprise, she can do anything)
evap harness disconnected on driver’s side of intake manifold

Coolant crossover lines to front and rear of heads disconnected
Radiator hoses removed at water pump, heater core hoses removed at water pump
AC compressor pigtail disconnected
MAP harness removed
hard hvac vacuum line removed
water pump out


Tonight’s work sucked!

Valve cover to throttle body vacuum hose removed
Throttle body removed
Intake manifold removed (needed to access OPSU harness).
Knock sensor disconnected
OPSU disconnected
Cam Sensor Harness disconnected
A/C Belt removed
Top and bottom AC lines removed (at firewall and at bottom of condenser)
Bottom 2 AC compressor bolts removed
Dipstick removed, Header (longtube) unbolted and moved down.
Starter removed. 3 large wires to main stud, 1 small purple wire to solenoid.

Crank position sensor unplugged.
Passenger rear block ground (15mm) unbolted. NOTE: This consists of 1 large ground wire and one very small ground wire (black with white stripe).
Passenger longtube header removed.
2 brake lines leading from master cylinder to EBCM removed
NOTE: This was a mistake! I ended up keeping the EBCM in the car.

3x pigtails disconnected from T56
1x pigtail removed from diff
wiring harness unclipped from retaining spring/clip on rear diff cover
4x 10mm EBCM bracket bolts removed, 1x 18mm bolt/nut for driver’s side steering rack/EBCM bracket removed.
Removed 15mm bolt on lower rear driver’s side of block, under header. Wire harness retaining bolt only (not a ground)
Removed 15mm bolt on lower front driver’s side of block, under header. Wire harness retaining bolt only (not a ground)
Removed 15mm bolt on upper rear driver’s side of block. 2x ring terminals (GND).

Rested cradles, front and rear, on evenly spaced jackstands.
Removed 8x cradle nuts.

UP 1"

Disconnected driver’s side wheel speed sensor at front lower cradle. The other end of this harness snakes all the way into the battery box and beyond.

UP 1"

Removed torque tube harness from L-hooks on top of TT.
Removed 15mm ground (2 wires into 1 ring terminal) from rear of driver’s side head.
Removed 13mm bellhousing bolt, driver’s side, that also holds wire harness in place (approx 10am position when viewing from rear of car).
Disconnect passenger front wheel speed sensor at lower control arm.


coolant fan wiring harness removed from retaining clips and unplugged from fans
Top condenser line bolt removed, condenser removed
Radiator removed (both will need power washing but are in good shape)
Since the brake system was already opened to install stainless lines, I disconnected the RF brake line from the ABS module to avoid having to drop the rack separately.
Rear large plug above T56 unbolted from retaining ring (T56 to TT)
Rear 9 o’clock TT to bellhousing wire retaining clip bolt removed
removed Battery box udder
4x TT harness large pigtails disconnected under battery box, unroute and droop down onto floor.
Raise body off drivetrain.



These pics are going back about a month.

I inspected the valves and found that there was some minor pitting on the seat surfaces. Never lapped in valves before, so here we go. How hard can it be? Actually easy enough that I had my wife do it…

The left (intake) is after, the right (exhaust) is before. Night and day

Apply magic goo

Insert valve into head, oil stem lightly.

Use the wooden tool for 10 minutes until you realize there has to be a more effective way than the Tom Hanks Castaway method of starting a fire

Break out the power tools and a length of old vacuum hose

After all 16 were lapped in they were removed (in order) and cleaned out with hot soapy water and a brush.

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Anyhow, moving to the fun stuff:

LS3 Stage II 3 Bolt Cam 225/238 .612"/.585" 113+3

VVT Comparison

Installation Prep

Hanging the Cam Retainer Plate by a bolt or two, and installing the bolts with red loctite.

Final Torque in a cross pattern.

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4x Cam gear, ARP hardware, and a simple LS2 chain damper. No spring loaded tensioner to fail.

Loctite and torqued to spec

L92 chain on left, LS2 on right. I don’t think there’s a difference. Didn’t have a Gen III chain to compare to, but I’m sure it’s wimpy compared to these two.

Some graffiti courtesy of the wife to let this engine know we mean business. (…it’s a cat…) sure honey, whatever you like

Obligatory “Dot to Dot” timing photo as evidence of correct timing if I have issues down the road.

Forgot to snag a pic of the cam gear being bolted down, but we used ARP bolts with red loctite torqued to spec.

LS7 lifters soaking for a few weeks ahead of assembly. Note the drainback holes in the lifter trays. When those get installed, they have to go towards the outside of the block to facilitate drainback.

Fun fact - a bore brush I normally use on my 870 12ga is perfect for cleaning and then oiling lifter bores.

Assembled into trays, which were scrubbed clean and blown out with brake parts cleaner and compressed air.

All oiling holes face towards the front of the engine (probably not necessary since the oil galley passes through on both sides, but that’s the way the originals came out).

Torqued down.


I left off that tonight taking stock of everything left to bolt up.

Factory L92/LS3 rocker arms with BTR Trunion Upgrade kit.

General stuff

Lapping turned out great.


While the top end was getting put together I cleaned up a couple things.

Borrowed a friend’s HF blast cabinet.

Valve cover bolts, before and after.

Valve covers after a bunch of blasting and scrubbing

High heat primer.

Used some old hardware to keep paint out of the threads.

I sprayed them with a nice VHT Wrinkle Red like I have on my LS6 intake manifold - makes for a nice pop without being tacky. Pics to come later

Checking for pushrod length. The 7.400" units that came with the cam kit ended up being the correct length.

Engine got rotated to get each cylinder on the base circle of the cam (compression stroke) for both valves, and the stock rockers with BTR Trunion upgrade were torqued down with the goofy 8mm 12 point bolt.

The new intake manifold gasket kit was picked up locally since I forgot to order it in my big blanket Rockauto order; it included the noise absorbing foam that goes under the intake.

Since the foam on the old intake was still in great shape, I just applied the new foam to the valley cover in the blank areas from the intake. I am really hoping I can fit the LS3 acoustic cover to keep valvetrain noise down. Don’t mind trimming the back a bit so that it doesn’t hit the cowl.

The intake manifold bolts got dusted off in the blaster also. Before:

LS3 intake manifold on:

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That’s as far as I could get on the motor for the day, so I wrapped it up and shoved it out of the way

The car went up on the lift and I started to tear it down. From a running, driving car to drivetrain out, it took me about 20 hours going slowly and labeling connections, taking notes about every disconnected wire, bolt, etc.

Rear tires are ready for a couple more months of use. These are Hankook Ventus V12s in a 285/35/19 and make for a great street tire. I even ran a few track days on them.

Exhaust components removed. Once I have the car up and running I’ll be relocating the cutouts to the rear mufflers to do a “bypass mod on demand”.


Just some notes about dropping the drivetrain:
-It’s easier to disconnect the rear diff, trans, and torque tube harness underneath the battery box and let them drop with the drivetrain than it is to leave them with the car.
-I left the EBCM/ABS module attached to the body (tied up with a string) but disconnected the brake line leading to the RF wheel so that I didn’t have to remove the steering rack.
-If I was only doing the engine swap I would have probably pulled the engine alone, out the top. However, since I need to replace my whining 4.10s, I thought it would be easier to drop the whole assembly.

That brings us to current day progress.
-My passenger inner half shaft rubber boot is leaking, I need to replace it.
-Need to measure the depth of the Y-Body LS1 balancer against the ATI Super Damper I bought and make sure it’s the same.
-Need to remove the batwing oil pan, clean it thoroughly, install the Improved Racing trap door baffles and Oil Cooler Thermostat block.
-AC condenser and radiator need to be pressure washed.
-My garage is a mess.


Are you going to coat those bolts you sand blasted? They will rust in quick order if not.


I was thinking the same thing. I would not have sand blasted em. Small detail though…

Great work, what did you have to bribe your wife with to let you take pics while she does all the work?


eh. might paint them. not a big deal to go back and re do them.

I bribe her with this D


My wife would never help document car time. Lol.


Got a bunch of little stuff done over the weekend.

Put the old drivetrain on some roll around dollies and moved it out into the open so I could start stripping some stuff off it. Those things are dirt cheap at HF and worth their weight in gold…

I transferred over the aluminum pedestals from the LS1 to the new motor. There is a well documented interference issue between the passenger pedestal and one of the bolt bosses on the block, so I ground down that area using a burr in a pneumatic die grinder.


Separated the LS1 from the rest of the stuff. I can’t wait to start reassembling, I am tired of tripping over parts.

Painted valve covers mocked up on the motor…still need to buy gaskets and grommets.

My LS7 clutch has only 10K on it; I’ll be reusing it


good work


I may have a potential buyer for the LS1 so I threw her on the stand and stripped the last of the items that I’ll be keeping (batwing oil pan, plastic clutch side covers).

I only use synthetic oil in all my vehicles and despite this engine being ready for an oil change, it was really clean inside.

I removed the oil pan pickup (which I am keeping and will eventually get cleaned out) and the windage tray (which is staying with the LS1). I couldn’t resist the urge to look inside the motor, it’s always interesting to see it has been treated over the years.

First time these components have seen daylight in this century (my car was built 1999 for MY2000).

Tough to see but there is still crosshatching on the cylinders.

I will try to get some more pictures with my Nikon before the LS1 is gone.

I also spent an hour pressure washing both the front and rear subframes in my driveway, after all the critical components were removed from them. They were covered in 17 years of grime and goo. No pics, just imagine someone throwing clumps of grease and dirt at you while spraying you with a hose.


Damn super good thread! Just went through it all. I had no idea that’s what the drivetrain on a vette looked like, now I know why @newman told me years ago that corvette’s have their tranny in the rear. The whole driveshaft tunnel thing is so WEIRD. I’ve never been under my car while up a lift so for all I know it’s the same thing.

On another hand, this thread reminds me of a post from probaby 8-10 years ago. Wasn’t there some guy on here who posted a pic of his chick fucking his shifter? he had the same shifter ball as @Norb_O I wanna say he had either a trans am or camaro. @LZ you know what I’m talking about?

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EDIT: This photo may not be able to be found, it’s from when NYSpeed used to be NSFW


Well seeing that I know who took it and know the girl the pic is still around :lol:



I definitely didn’t see the picture lol


Ah the good old Random Jailbait Thread days…