I just pressed out the valve guides on a couple of heads I have here and I noticed that the exhaust ones were almost melted all the way down to the guide boss. Is this just a wear type thing or was there something seriously wrong with the engine?

I am thinking about using the magnesium guides anyway. Would this be a good idea?

Also if I use the better type guides would it be better not to use a valve stem seal on the exhausts like vizard says?. I am assuming this would make them less inclined to melt?

Thanks ya'll

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These days with unleaded fuel unless you are using 21/4N stainless steel valves with unplated stems (like me) I would use the stock cast iron guides.

The other guides you are thinking of are manganese bronze, not magnesium (which would last about 5 seconds).
these are the ones I use in my 1360 for reason above.

I never use valve stem seals on the exhausts, there is no vacuum there (unlike the inlets) and as Vizard says they need some lube for heat transfer. Particularly bronze ones- they can seize with no lube.

I know that BL/Rover fitted seals to all 8 valves from around 1980 onwards, but they are pretty ineffective once they go hard. It doesn't take long at all....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.