a friend gave me a cherry set of 2.0 3 bolt heads. while i was cleaning them up this morning i noticed that 2 of the valve guides are threaded on the inside. one intake and one exhaust..... has any body ever seen this. i have no history on these heads, but from what i can tell, they have seen very little use. if any.

The process was known as a knearled guild. running a tap down a oversized guild then reaming it to fit the valve stem. It was used on heads that the guild could not be replaces, it was said to be a ok fit because the threads heald oil and lubed the stem. Our heads are easy to replace the guilds so that is the way I would go.

hmmmm.... the exhaust is only threaded about an inch in. and the intake is threaded may 3/8 of an inch, both from the rocker box end.

True, but it was more of a forming tool. Similar to a roll tap. It was the cheap way to fix old cheby heads. It would work for a short while, but what it did was create less surface area in the guide, promoting even faster wear. Auto parts store machine shops used to do it all the time.

Put new guides in. They are cheap and relatively easy on the T4 for a good shop to do..

...they stopped when they realized their mistake on these heads.

Send them to one of our top talent advertisers on this site. They all do the correct work that is required.

Great find, by the way...

im bummed. i want to continue, but i cant ignore this. my wife is tripping on the cost of this......

You can do it right once or you can do it wrong multiple times. In the end, doing it right is the cheapest way to go.

The knurling treatment to the valve guides was ok on water cooled heads, but not air-cooled heads.
The valves stems need as much contact as possible to conduct temperature from the valve to the head.