So I had a mishap in my 01 Z06 and looks like I need a new motor. I can find LS1's from Fbodies ALLL day for cheap. I will be installing aftermarket heads and a cam so I could care less about those, but if I were to get a low mileage LS1 short block for my Z what would I be short changing myself on if anything.

 

Only thing an LS6 had over an LS1 really was 243 heads (and the LS6 Intake, but 01-02 LS1's had the LS6 intake anyways).

With aftermarket heads/cam I would just get a LS1 shortblock (maybe LS2 if you could swing it) and go to town.

 

i think the valley cover is different also, not 100% sure but i think it is

 

Yeah, forgot about that; I think the LS1 valley cover can be modified because I know people do the mod. I'd just swap them over I guess off the other motor.

 

Scoggins Dickey is selling the LS6 long blocks for $3250 shipped and you could sell the heads/cam and springs for some of your money back and have a new zero miles motor.

 

The ls6 blocks also had breathing "windows" between the main bulkheads and the cylinders, while the ls1 blocks have a smaller hole drilled through the main bulkheads. Truck blocks get a cast window, but in the ls1 location (i'd have to go look to be 100%) l33 (ally truck block, 05+) gets the ls6 window location.

GM has been making the windows bigger as they progess with this engine family, and the ls9 has the biggest windows yet.
Little writeup here:
http://www.camarohomepage.com/ls3/

 

I believe those holes you speak of are only on early 97,98 blocks. Not to sound all roman on you. Just make sure its not a block from those years as GM improved the breathing between the cylinders, oil passages, and im sure im forgetting something else. If your going aftermarket heads/cam that plus the intake were the major differences between the ls1/ls6. Short block is the same.