I have a set of supposedly low mile (2x,xxx IIRC) Z06 243s. I verified that the valves are hollow and the heads "look" like they could be low mileage. I'm installing the Comp trunnion upgrade and an all-inclusive dual valve spring kit. I dug around on the 'net for a while and I'm still not sure one way or the other if I should give these heads a simple lapping. I found plenty of debates on lapping after a full-on valve job, but that's not what I'm doing. I recall reading that, in stock form and fresh out the factory, the valves don't seal to the heads as good as they could. I'm just talking about giving them a few rubs with the finest grit I can find and checking them with Prussian Blue or something like that.

If it matters, these are going on an LQ9 with a 226/230, .598/.600, 113LSA, 111ICL, +2

 

It can't hurt, just don't go crazy and take your time using a fine compound and you will be fine.

 

I run fine grit on all my heads before I install them. 1. it gives a fresh true sealing surface, and 2. if something is amiss, you'll notice it before your engine is together. I've found from my limited experience that when a valve runs true, the sealing surface is clearly visible in the compound around the perimeter. I don't see why this would require any prussian blue.

 

That's pretty much the same thoughts as I had. Thanks guys.

 

I don't recall the name of the place, but there is a kart parts place in Virginia near Williamsburg that specializes in Briggs & Stratton cart motor w ork. They have a lot of different grits of lapping compound with a lot of nice tools to do the work. I got my compounds from them when I lapped my stock heads and my Dart heads.

Just make sure you clean the heads really well afterwards so there is no grit left.

 

^^^ I'll look them up. I'm definitely taking my time and researching as much as I can while I have the motor torn down.

Thanks for the info.

 

I would get a valve job done if you have the heads off the motor for a few reasons. You will pick up flow with the valve job and the heads should seal no problem if you have someone reputable do a quality 3 angle valve job for you. If your knowledgeable with cylinder heads I would then blend the valve job in and do some bowl work. You can pick up 30CFM on a head and lose no velocity.