bly123

Hi, I have a 98 C5 and I purchased the LS6 heads and intake manifold off of a 2001 Z06. I understand that both the heads and the intake flow way better and can improve my performance.

Putting aside all the should do's, like cam, and headers, and oil pump, and timing chain. I'm Not saying I'm not doing it.... but....

"(Is this a plain swap)?" can I swap heads and intake with all the stock things hooked back up to it? Like the exhaust manifold and other stuff?
I'm doing it in stages and my stage 2 is heads and intake. (With tune of course) My stage 1 was Borla cat back, and Vararam cold air intake.
In a year or so I will do the cam and long tube headers and everything involved with that. I understand I will be taking it all apart again when I do that. I'm not rich so I have to do it in stages.

If it is not a plain swap what will I need to do to make this work with my 98 ls1 c5 vette?

Thanks!!

Smokin Joe

Catback is so negligible as to almost be irrelevant. LT headers is big. Do it first.

Talked to the owner of HPSales in South Florida two weeks ago. Planning out my mods. Cams get more bang for the buck then heads. I would do cam only or cam with heads. Not heads only and cam later. That's based on the vendor. Before talking to him, I was leaning heads and cam at same time anyway, with some other stuff to support it.

LS6 heads are ok, and will help, but not worth anything without a cam. LS1 heads and a cam are probably better. Again, this is my interpretation, based on a specific vendor. Anyone, jump and correct me if I'm wrong.

bly123

Ok thanks for the info. I do appreciate it but. My question is "is the ls6 heads and intake a plain swap and if not what needs to be done". I understand what your saying and I appreciate your advice. But can anyone answer the specific question? Thanks.

Blow Torch

Yes, it is a straight bolt on.
You will also need the valve covers and coil pack brackets (98 is parimeter head and 99 up is center bolt )
You will also need to get the Z06 (2001 and later) coolant crossover lines (ones that go under the intake). The Z06 intake will not work with the 98 crossover lines.
Get Head gaskets for something like a 2001 and later. (98 has different gaskets)

bly123

Great! That's the info I was looking for. I was concerned there was going to be allot of modifications. I thought I saw somewhere that the 98 exhaust manifolds might not fit the LS6 heads. Or the ports don't match up. That not true is it?

78GEN3

I have an LS6 block, LS6 intake and 243 heads in my 97. Everything bolted straight up including the exhaust.
The only thing I had to modify was the coil brackets like mentioned above and the PCV system to work with the center cover, which won't be an issue for you.

I have the stock exhaust on now, and I did install a cam. Simply for the fact that I was replacing the engine and it would have been more difficult and costly to do it later. I do plan on LTs in the near future, but I would have done them first otherwise.

For what a cam install costs you can have the LTs, and then when you do a cam later it will benefit even more. If you got a great deal on the heads, awesome, just set them back for when you can do the cam and heads at the same time.

bly123

I think that's great advice. I'm going to do the intake now and the heads in the fall when it's cooler outside. It's 100 degrees in Texas. I'm thinking,, why not get the heads ported and polished. And the it headers in the fall.

Smokin Joe

Sorry, I didn't read your post accurately.

bly123

It's fine. I'm just glad you took the time to share your knowledge.