I am doing a h/c and port and polishing the LS6 heads and upgrading springs to PRC duals, do i need to lap the valves?
Is there anyway you can go wrong while trying to lap the valves, seems simple enough if i have to do it.

 

Have the heads been run? Just re-built?

 

Have any of the valves been moved from their original cylinder?

I'd say yes if so.

 

These are the stock heads which i am going to do a mild P&P on, and not gonig to mess with the valves.
I have removed the valves, but i arranged them in a cardboard box so that i know which valves goes in which cylinder. That way the valves will stay in there original positions.

 

Then no

 

Simple enough
Can i clean the valves uing carb cleaner, wd40 and a scotchbrite pad, or will the scotchbrite micoscopic scratches cause them not to seal properly.
I am trying to clean all of the carbon build up on the engine and heads, which has worked with the above method, and would like to get the valves as well, any tips.

 

Use Piston Clean and soak them or hot tank them

 

You should lap them to check for proper seal anyways, instead of a scotchbrite pad, use a brillo pad (steel wool) - lap the valves after to check for a good seat width & pitting.

 

How many miles are on your heads?

 

Lapping is easy and a ten minute job. I always do mine when apart with ultra fine (600) to ensure they correctly color. Just make sure you get all of the compound off the head and the valve.

 

Almost 40,000.

I guess i just going to lap them once i am done to play it safe. Do all parts store have the lapping kits, and do i need 2 different componds or just go for the ultra fine grit.

 

If you go through the trouble of lapping then just get a valve job and do it right.
Either do it all the way or don't do it at all.