I built this boosted LT1 and I'm running OE head castings. I worked the heads a bit and installed stainless valves, new double springs and had a 3 angle valve job , but I did not have the valve guides replaced. The heads have about 114,000 on them now.
What I did do to the guides is have the outside diameter machined down from the stock .557" to .530" so I could find a valve seal which fits inside the new double springs. I found some, but I am using a couple quarts of oil per week. Plugs are almost immediately oil fouled. If you stick your foot under the 4 inch exhaust pipe, your new white casuals are going to be ruined. I actually had a mist of oil spray covering the back of the car.
So, after tearing down the engine, I found that the rings are all installed correctly, but the valves are absolutely coated with burnt oil, and the valve stems have oil all over them.
It seems that when my valve guides were machined to .530", they did a terrible job of keeping the cutter on the same axis as the valve guide--in other words, when I install my valve seals, they are slightly crooked.
So I don't know if my problem is caused by that, or worn guides, but either way, it seems I need new guides.

With all of that history, HERE IS WHAT I NEED TO KNOW:

I need to know what price range I should expect to pay for new guides and installation?

I need to know if you can get guides which are already fabricated to fit our head, AND a .500 or .530 valve seal with an 11/32" valve?

Anything other useful related info would be cool too. If its going to cost alot, I guess I'll trade these heads in for cash at the scrap yard and buy a set of Darts.

 

A good machine shop (obviously not the one you went to before) will have quality guides in stock, most of the time in the size you are looking for. That sounds to me like it is definitely your problem. The only other thing it could be and I am SURE its not is that the pin height is in the ring lands.

 

what do you mean by this, "the pin height in the ring lands?"

Also, it looks like I'm just going to order a bare set of Darts and switch my valve train over with some new exhaust valves...i toasted my old new ones thanks to false AFR readings from all the oil in the exhaust!

The reason for going with new heads is, to me it is not worth putting hundreds of dollars into new guides and another new valve job plus labor. The darts will give me a higher quality peice at this point and a small performance gain. If I have time, I will do a mild port and polish on the Darts and pick up a few more ponies.

 

I believe he was maybe talking about on some pistons the wristpin is located up so high it is actually into the oil ring.

 

That is correct!