fitting valve guides

[spitfire4v8]

Have any of you enterprising home modifiers replaced valve guides? The official line is heat the heads to 65C which might be a problem. Am I just better off handing it over to an engineering firm that does this kind of thing, or is it perfectly possible to do it yourself? Sardonicus .. maybe one for you?
Process sems to be, heat head, press in guides to depth, leave heads to air cool slowly. ream guides. cut seats .
I'm happy with everything except the heating the heads bit ..

[spitfire4v8]

Should have said it's a pair of rover heads I've ported. The guides are out so I need to fit new .. cheers for the reply.