Axiomiat

My LS1 runs great for now, but I want to do a swap in the future.

There's lots of threads on LS3,7 swaps but I'm finding it hard for parts other than the engine.

Like headers I know are larger for the LS3 so I'm holding off on them.

I'm going to replace the AC compressor now and while I'm at it, I'm looking at putting in a performance radiator.

So my question is: What major ($$$) parts can't cross over to an LS3 in the C5?

Anthraxmm

Ls1 headers will bolt right up to ls3 heads it's the intake that has to match.

redcycle13

The intake will be different if using LS3 heads. Then the stock throttle body will not fit the new intake. Rocker arms are different for LS3 heads too. The front engine cover, and timing gear are different. Those are just a few things off the top of my head that can catch you off guard.

Armycop

plus the camshaft and crankshaft signal wheels are a 57x reluctor, whereas the LS1 PCU takes a 24X reluctor cycle, so you'll either have to swap cams and crankshafts or get the Lingenfelter reluctor 57 to 24 step down box installed.

dr_whigham

58x

Axiomiat

Great info here! Thanks!
Are you guys talking about what needs to change if you put an LS3 block in? or a complete engine? I was going to do the complete engine brand new from Chevrolet. Great to hear about headers.


And most other parts around the engine work the same too? Like a C5 radiator works with an LS3?

I'm just putting oil in the stock LS1 and upgrading around it (suspension, wheels, brakes, interior) till it dies. I just want to hold off on anything that would have to leave with the LS1 when it's taken out.

968ls1

I am in the middle of a ls1 to ls3 swap now. Here is a list of things you will need.

LS2 Silver Blade Throttle Body-(Rockauto) and Conversion Harness Casper's).
Knock Sensor and Cam Sensor Relocation Harness (Casper's Electronics)
MAP Sensor Harness or just extent the wires to the front of the intake.
58x to 24x Crank Harness (Lingenfelter) or change reluctor wheel on the crank-that's what I did since I was building a motor.
Depending on the year you might have to convert wiring for the MAF/ATS sensors to a 5 wire.
Modify (Clearance) engine mount on drivers side for knock sensor and drill and tap to fit LS1 style sensors.
Upgrade the clutch.
Check/Rebuild your torque tube if you have high mileage or hard usage. (Guibo's and Bearings)

My 99FRC was pretty tired so I went through the whole car.
I did C6 Z06 Brakes, Bilstien Shocks, Z51 C6 Sway bars, RPM trans and cleaned the crap out of everything.

LoneStarFRC

Your motor mounts appear to be polyurethane aftermarkets pieces. I would make sure to use heat shielding around them. Polys do NOT like header heat.

968ls1

Yep, I wrapped them with DEI heat reflective shield as well as the tunnel plate and starter.