LS3 top end swap

[Chester Copperpot]

So I FINALLY got around to starting to tear all my stuff off after I said I was going to two weeks ago. Stupid real life stuff and Luke's.

Swapping out my LS6(243 cast) heads and LS2 intake for LS3(823 cast) heads, LS3 intake, and 42# injectors.

Battery and Vararam intake taken off

Coilpacks, throttle body, and strut tower brace taken off

Driver side rocker cover

Passenger side rocker cover

Intake Manifold off

Intake runners taped off and valley cover and heads cleaned up

Table of stuff removed(also under it) (Also no Jeremy, that is not shit all over my Jeep)

Cracked the head off and coolant poured EVERYWHERE and some left in chambers

I was surprised at how clean the heads were. This is the passenger head but the driver head looks identical. Not bad for 84,400 miles.

Coolant cleaned off and not too much carbon build up.

Gasket residue and carbon all cleaned off.

Driver side bank. Again, not too bad carbon build up.

Gasket residue and carbon removed, all clean.

Pulled the valley cover off to clean the edges off

These all shocked me. These are the eight passenger side lifters and they all looked damn near BRAND NEW. The driver side were identical. It just amazed me how clean the rollers were.

Click to read more...

 

[32vMonte]

Looks good, how did you clean the carbon and gasket stuff off?

 

[TransHed]

Tiiiiight

 

[Jean Ralphio]

what kind of gains are you expecting?

 

[Smokinhot]

 

[Shibby50]

what kind of gains are you expecting?

This and looks good so far man!

 

[AlwaysVTEC]

sell me your 243s

 

[Chester Copperpot]

Looks good, how did you clean the carbon and gasket stuff off?

I sprayed some PB blaster on the pistons, just soaked up the extra, then I took a 4" razor blade on a handle with the piston at TDC and just worked the carbon off. Then I did the same for the gasket material, being mindful of the coolant passages.

Tiiiiight

Kitties got titties.

what kind of gains are you expecting?

Hoping high 400s once I get everything done. I may aim for 500 once I port/polish the heads/intake mani and get everything done in the engine but since I'm an auto my power is going to be a bit lower than my M6 counterparts.

sell me your 243s

Sorry, I said SirMarco could have em waaaaayyy back when I first got the heads and was getting all the pieces together. My bad.

 

[Chester Copperpot]

Aaaaaaaand bump.

Just got my heads back from the machine shop. Milled .030" to a total height of 4.702" to keep the stock 10.9:1 LS2 compression. Pretty shiny, too.

Driver side on

Passenger side on

Rocker covers on

"Stock" lolz

Also... in the span on 5 minutes of putting my battery in for the first time in two weeks, somehow BOTH of my fucking doors locked and both of my keys are sitting in the cup holder because I stashed them in there when my parent's house was getting shown in an attempt to sell it. Pretty pissed off about it... 2 weeks of work and waiting to be shattered by 5 minutes of some stupid bullshit... :rage:

Oh and all my LS2 stuff, as well as my 243 heads are up for sale. AlwaysVTEC, I tried PM'ing you but I didn't get a response.

 

[Mook]

i enjoy this thread.

 

[Chester Copperpot]

In Soviet Russia, thread enjoy you.

 

[udluuz]

Nice. Done yet? How does she run?

 

[THEHKP7M13]

Sucks about your keys. Still learning my GTO. I want to disable those automatic door locks..annoying.

What is the major advantage ofthe LS3 heads?

What did the machine work cost?

Between the cost of the heads and Machine work would aftermarket heads been a better choice?

 

[OffshoreDrilling]

Are you switching cams too? Whatever you have in there now, whether stock or aftermarket, isnt going to work that great with the l92s. They have a hyuuuuuuge intake port compared to a cathedral port head and need to be cammed much differently. Good work though, l92/ls3 heads are an awesome budget head!

Whoever picks up the used 243s, send them to total engine airflow to get cnc'ed.

 

[Chester Copperpot]

Nice. Done yet? How does she run?

Totally didn't realize my own thread had responses. It was done the day I posted this. It wasn't so much a build log as oposed to a completed log. Runs sorta well. The guys at the Byron track day know what's up.

Sucks about your keys. Still learning my GTO. I want to disable those automatic door locks..annoying.

What is the major advantage ofthe LS3 heads?

What did the machine work cost?

Between the cost of the heads and Machine work would aftermarket heads been a better choice?

I don't think you can disable the auto door locks. Pretty sure you'd need one of the GM programmers to disable that shit.

Major advantages are that the intake runner is more free flowing as cast. The intake valve is larger. Only downside is the exhaust runner doesn't flow too well but I've read and heard just a basic polishing does wonders for the exhaust side. Stock LS3(0821 cast) heads flow about the same as completely worked over 243s.

Machine work was $125 just to mill the heads. I honestly didn't feel like dropping $600 bucks to port heads that flow phenomenally as cast. Maybe I'll learn to do it myself and just touch them up.

After everything was said and done, EVERYTHING(heads, springs, valves, retainers, rocker arms, intake manifold, fuel rail, 42# LS3 injectors, milling, head gaskets, ARP bolts, and coolant) cost a total of $1600. Stage 2 ported L92/LS3 heads(no intake manifold or injectors) cost upwards of $1700. Was definitely worth the money for the entire top end.

Are you switching cams too? Whatever you have in there now, whether stock or aftermarket, isnt going to work that great with the l92s. They have a hyuuuuuuge intake port compared to a cathedral port head and need to be cammed much differently. Good work though, l92/ls3 heads are an awesome budget head!

Whoever picks up the used 243s, send them to total engine airflow to get cnc'ed.

I'm still on the stock LS2 cam. I'll be getting my cam some time by the end of the year. I'm aware of the cam difference between cathedral and rectangular ported heads. HUGE thread on LS1GTO about it.

Someone picked everything up about 3 months ago so they're long gone.

 

[Shibby50]

I was actually looking into doing this for a while. Does the stock ls2 TB bolt up to the ls3 intake? Was wondering what people used with a cable TB for pre-05 LS cars.

 

[Chester Copperpot]

If you have an LS1 in that TA still, the LS3 heads wont fit because of the bore difference and the size of the intake valve. Mast makes some LS1 "L92/LS3" heads(rectangular port, etc) but they're pretty expensive.

Yes, the 90mm LS2 TB bolts up to the LS3 intake. I think the LS3 TB is 95mm(not quite sure)