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Pulled the motor to do a cam swap among other things... Heads are a pair of stock LS7 castings that Greg Good worked his porting voodoo on. However, Cylinder 5 exhaust port looks like it has a tiny crack (casting flaw?) right up next to the guide.
I'm pretty much at a loss on how someone would even go about "fixing" it. Obviously no sort of epoxies would hold up to the heat. Welding doesn't seem like an option, as I'm guessing that much heat next to the valve guide probably isn't good. There's a tiny bit of oil there but I don't see any smoke out the exhaust... Thoughts? Should I even sweat it?
If there was too much material removed from there it might have been the reason for the damage. I would recommend that you clean that port really good and take another look. There's a lot of carbon buildup and it makes it hard to tell how bad the damage is.
Clean the port and take another pic.
If there is damage you can talk to a cylinder repair shop and see what they say.
Ok, it looks like it was just me being paranoid... I cleaned the port up the best I could and I didn't see anything noteworthy. I purchased these heads new back in 06' and Greg did an excellent job on the port work and assembly. I just got an E-mail from him, so looks like this is ready for the archive:
The guide boss on the exhaust side is about an inch thick, so there is no way any crack would get even close to oil. It's normal to see a trail of oil coming out of the exhaust guide, and it's good to have. That means the guide is getting some oil. It happens on the intake side too but you don't see it because the fuel washes it away. I've seen a lot bigger oil trails.
Last pic is way better. Just an oil trail. No worries, but I'll be happy to lap the valves in and check the guide clearances, etc.
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Should I be concerned? Ported LS7 heads.. 
