I need some help

[Chad S. Becker]

Bear with me for a moment....I bought a motor sold as an LS1 block with all internal/head components from a wrecked 2006 Zo6. The block had a busted arm/bracket, hence the new different block. At the time, it was listed on Ebay motors as an LS1 block with all the "LS6" internals. Now after some reasearch, I now know that the '06's had LS2 motors.

In short, I'm trying to verify exactly what I have. The block casting confirms it as a '97 LS1 block. The head casting is 243, which denotes either LS6 or possibly an LS2 if my research is correct. The intake manifold numbers confirm it as an LS2 intake.

Here is where I start wondering. The new motor's exhuast ports (at a glance) look a bit smaller than the ones on my old '02 LS1 because they are flat (d-shaped) at the bottom. The other ones were round/oval. Then I done some further research, and they say the "D" shape denotes either an LS6 or LS2 exhaust port.

I don't exactly trust the seller, so I wanted to ask someone on this forum.I don't know what the heck I have! If anyone could give me some guidance here I sure would appreciate it...alot.

[mark21742]

If I'm correct, the 97-04 z06 had a ls6 block (basicly the same as the ls1 but better oiling and slightly stronger)
243 heads (casting number on front passengerside and rear driverside up next to the valve cover)
Ls6 intake (no egr tube behind the tb)

The ls2 blocks have the cam position sensor in the front timing cover and are 04 or 05 and up

[Chad S. Becker]

Yeah, I'm still not sure exactly what I have yet, but leaning toward ls6. Since the innards were taken out of the Zo6 motor and put into an ls1 block, I'm guessing it has to be all ls6 internals due to the difference in bore on the ls2. I have no idea how to tell the difference in the 243 heads unless I pop the covers and look at the springs.