Which 243's are these
 

I just bought them and was told they were off an 02 vette and yes the say 243

Here's another

And another

One says 62 and the other says 63

02 vettes came with 241 heads

02 z06 vettes came with 243 heads

Pull a couple valves and weigh them, if they are the lightweight hollow/sodium valves (ls6 engine) then they could have only came from 2 vehicles

2002-2004 corvette z06
2004-2005 ctsv

If they are the solid valves then they could have came from a number of engines like...

2001 corvette z06
Ls2 gto
Ls2 Corvettes 05-07
Gen 4 truck engines

Either way 243 heads are good, not all 243 heads are ls6 heads. Ls6 heads are only the 02-04 z06 and 04-05 ctsv.

So there is no difference in...
The castings, Flow #'s, or Valve sizes?

No. They are all basically the same

LS4's came with them as well, oddly enough.

Nice

They are a great budget head no doubt.

Ok the guy just told me they were off of an 01 Vette, can anyone tell what springs they have?

Full blue valve springs = 2001 ls6, does not have the lightweight valves.

Ok, what lift are the springs good to?

stock.