c6reaperx

So I was going to install a ported intake, tb, and lg headers on my 05 today. I noticed that my intake manifolds did not match and after running the numbers it seems that the ls3 heads and intake are already installed on my ls2 block.

I purchased this car nearly three years ago and have been fighting some issues. I need some advice on that to do next since I want to keep the car since I almost have it paid off.

Should I just roll the heads back to stock ls2 or get a new intake and install the headers that I have?

Looking around the site, it looks like the headers would work but for the ls3 heads to work best on the ls2 the needed to be milled prior to be in installed. I have no way of knowing if that was done.

I have emailed peak speed to see if I can swap my intake, so I'm leaning towards an ls3 intake, the ls2 headers, and taking the car to Henson motorsports for a tune.

What would you do?

AJG87

You've introduced three options alone concerning an intake manifold..You're a bit all over the place in your post.

What issues are you having? What intake did you plan on installing if there's already an LS3 intake on your engine now? What intake do you want Peak to 'swap' for you?

c6reaperx

Until today, I thought that I had a stock ls2. I had planned on a peaks radical intake, headers , and a tune. Since I cannot use the ported ls2 intake that I purchased I was going to swap it for an ls3 ported unit. Just wanted to know of the whole setup would work, or if I need to take another direction.

c6reaperx

The car has had an issue running rich since I bought it. The dealer could not tell if The car had a tune on it or not, so at this point I feel like I have a ls2 low end and ls3 top end that's running a stock tune.. The lower end of the engine , cam down, was rebuilt by the selling dealer shortly after I purchased the car. Its been a thorn since I bought it, but today's revelation is making more sense of it all.

berk4422

Here is what I would do, i would post on the for sale or trade and even swap. I am certain there is someone with an LS2 that would love an LS3 Top end. You can swap back to stock with no problem. Then you can mod from there. If I didn't already have headers and a fast 102 for an LS2, I would have been all over this. Good luck!

Or, just get new headers for an ls3 and a tune...

c6reaperx

I have no problems keeping the ls3 setup but I'll have to look at the headers to see if the mate up. I guess the biggest worry is ...were the heads milled to spec to keep the comp ratio

sevinn

The only way to know for sure would be to take the heads off and doing several measurements.

If I were you I would just get it properly tuned with the headers and go from there.

Big ol 68

The LS2 headers will work. You cant get ls3 headers for your car. They wont fit. The routing for the exhaust was rerouted in 08 aka for the ls3. LS2 headers will bolt to the ls3 heads. I'd just take your car to a good tuner. The stock LS3 top end on a ls2 bottom end already flows plenty. No need to port anything. You can have to much air flow. Guys who have ported there ls3 top ends on ls2 bottom ends have reported loses of power because of to much airflow. I'm in the process of doing the swap myself.

The milling of the ls3 heads. .030 is about all you can take off. Anymore and you run into piston to valve clearance issues. Milling the heads will bring the compression ratio closer to stock and bumping the hp a little.

Like I said, just bring it to a good tuner and tell them all you know and let them do what they do.

Zip Corvettes

Hold on, the LS 3 and the LS2 are noticeably different. Google a picture of the LS2 Cathedral port cylinder head. The LS3 has retangle port heads. Plain and simple that will tell you if you do or do not have LS3/L92 cylinder heads. Either header will fit the car, the exhaust was redone in 09, not 08 and it is the rear y-pipe that was redone. As far as what to keep, depends on what you want to do with your car. If you are after power, then stick with the LS3 setup. If you just cruise than go back to the LS2. The LS2 was and still is an awesome engine. I wish you could still get them.

c6reaperx

Thanks guys. I ran the head pn (823) and they come back as ls3. So the ported intake would not do anything positive for me?in that case I have a new peak speed shop radical ported unit for sale.

c6reaperx

c6reaperx

I was just thinking this over and remembered that the crank, cam, and lifters were replaced under warranty shortly after I purchased the car. So let's say that the shop used stock ls2 head gaskets for the 823 heads. Do I need to be concerned about that and if so, what gaskets should I use in place of them.



Thanks everyone for you help.