had my heads resurfaced by a very reputable builder and he vacuum tested the valves as well and said they were sealing fine. I need to remove the valves to install the new stem seals, should i lap them while they are out or leave them alone since they are sealing?

 

I had mine done while they were at the head shop n they replaced everything. I didn't have to go back and do anything

 

Hey, while you have the heads off why wouldn't you spend some time and lap them? Better to find out that one of the valves is barely within sealing tolerance now vs. when the heads are installed. No brainer.

 

Lap them sombitches.

 

Go one step further and get a proper 3 angle valve job. They all need it.

 

Lap or valve job no way they go back on my motor with out one or the other.

I had a rover v8 go from a misfire to no compression due to a valve in less than 2k miles

 

That's my thoughts also. You already got it down, might as well get it done right the first time instead of having to take a chance and hope it works outs. Better to spend a little extra up front that have to do it all over again and it cost you more. Heck you would think a reputable head shop wouldn't even ask that question, especially since they know what the heads came off of.