Building a l92/ls3 upper swap shopping list....

2798 Views 9 Replies 6 Participants Last post by AAIIIC, Apr 7, 2022

Kags1969

Discussion Starter · Jun 22, 2011

So I am trying to find the most cost effective horsepower available and I think that LS3 Heads may be a really good option. I have been reading here, ls1tech, ls2gto, corvetteforum and various other places about swapping ls3 heads onto my LS2. After reading here is what I think I will need and various prices:

LS3 heads - $750/pair from sdparts
Comp Beehive springs ~ $180
Takeoff LS3 Intake/fuel rail/injectors - $290
LS3 head gaskets/bolts ~120
LS3 Intake rockers and pedestals ~130
Texas Speed 224R 224/224 .581"/.581" Camshaft - $380
Dynotune - $450
Sell 243 heads and intake ($400)

So for ~$1900 I think this will put down some good numbers and be very street-able.

I know that it is fairly common for the GTO guys to mill the head .030 to get back to stock LS2 compression, I think this adds about $100, just not sure if its worth it...

I can do the install myself with a buddy, so only beer cost there...

Am I missing anything? looking for constructive input....

The only real downside I see on this setup is that it eliminates adding a maggie later on....

Kags

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trukk

· #2 · Jun 22, 2011

What about a new timing chain? I'd do that just for peice of mind.

Also will your new combo support your current fueling capability? Any idea what you injectors are currently at?

Are you going to re-use your stock pushords? Seems odd to do all that and not replace the pushrods.

Also, depending on how many miles you have, when doing heads, it's a good opportunity to do lifters.

Don't forget the misc stuff:
- Head gaskets, intake manifold gaskets, new harmonic balancer bolt (andy any other fasteners you may need),fluids (radiator, engine oil, cam lube, etc.)
etc. etc. etc,

What about tunning?

And so the slippery slope goes.....

-Chris

P.S. I'm captain overkill. My cam swap cost about $4k with parts, labor, tuning. Been running no issues for 70k miles this way though. Remember: Cheap, Powerfull, Reliable -- Pick 2. I went with the last 2.

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JSR

· #3 · Jun 23, 2011

I did the swap and it looks like youve got most of it. The LS3 injectors will only be at 75 - 85% duty cycle with that combination. One thing I wish I would have done was motor mounts when the heads were off. Biggest thing to get the most out of the combo is get a good 5-angle valve job on the intake and a continuous radius on the exhaust along with the decking 0.030". Definitely invest the $12 in the pushrod checker to make sure you get the right length. As for the cam specs, I think you can go bigger. What about fly-cutting the pistons?

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wcryan

· #4 · Jun 23, 2011

would milled LS2 heads be just as good as LS3 heads?

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Kags1969

Discussion Starter · #5 · Jun 23, 2011

The LS3 heads flow much better out of the box. Now if you were to send the ls2 heads to TEA or AI and had them ported (1k-1.5k) then they would flow ~ the same/better then ls3 heads....

- It seems like on the ls3 heads you really dont have to go crazy with the cam to get good results...

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wcryan

· #6 · Jun 23, 2011

700 for a pair is almost as good as paying 1200 to port them.... but the only downside with the LS3 heads is everything else that must come with it

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Kags1969

Discussion Starter · #7 · Jun 23, 2011

The other challenge with the ls2 setup is the intake doesn't flow nearly as well as the ls3 intake. So if you port the LS2 heads you are then dealing with a restriction at the intake.. The Fast102 stuff runs about a grand if you want to upgrade in that direction (do you have to get new fuel rails with the fast or will it work with the stock stuff?), but a grand for an intake just hurts my feelings...

I have been reading that the intake upgrade for the LS3 guys (to the fast) doesn't yield near the results as for the ls2 cathedral head guys...

I have to fight the urge to buy AFR 205 heads and then slap a Maggie on it... I am trying to find the sweet spot on the power to cash ratio....

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wcryan

· #8 · Jun 23, 2011

hahaha........ You'll never meet in the middle with that kinda ratio.

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2011cts wagon build

· #9 · Apr 7, 2022

JSR said:
I did the swap and it looks like youve got most of it. The LS3 injectors will only be at 75 - 85% duty cycle with that combination. One thing I wish I would have done was motor mounts when the heads were off. Biggest thing to get the most out of the combo is get a good 5-angle valve job on the intake and a continuous radius on the exhaust along with the decking 0.030". Definitely invest the $12 in the pushrod checker to make sure you get the right length. As for the cam specs, I think you can go bigger. What about fly-cutting the pistons?

You did the swap? what rear end are you using? i got a v6 cts and I'm ls swapping with the ls3, I don't know what rear end I need to make it all work. help me out. text 443-569-2415

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AAIIIC

· #10 · Apr 7, 2022

2011cts wagon build said:
You did the swap? what rear end are you using? i got a v6 cts and I'm ls swapping with the ls3, I don't know what rear end I need to make it all work. help me out. text 443-569-2415

Before you quote a post from almost 11 years ago, do yourself a favor and click on the user's name. That will take you to their profile page, which shows you when they last logged in on this site. In the case of JSR, it was back in 2012, so it's highly unlikely that you're going to get a reply from them.

As for what rear end to use, it would help to know what car you're working on. You've bumped an 11-year-old thread in the 1st gen CTS-V forum, but your username implies that you're working on a 2nd gen CTS. If that's the case, then asking someone with a 1st gen CTS-V what rear end you should use is pointless, because it's not the same as your 2nd gen CTS.

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