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I'm re building on the cheap, a valve froze in the head, I'm doing some minor port work, matching gaskets and smoothing chambers, i was researching replacing valve guides and some of the companies make it sound very difficult and even dangerous. Oversize stems seemed like the safest solution, apparently the exhaust guide may pass through a water jacket and gm my not have bored there stems straight. WHAT SAY YOU
If it has to be done at home cheap . And the seats look ok . Then change only the valves that are bad with over size stem type . I think you may need this 3/8s valve guide Flexhone to fit the new valves . There made by BRM #8538 and cost $14.95 You can buy them and the over size valves from Competition Products Also hand Lap all the valves to the seats. And install new spring and locks .
well on big block you can drive out the stock guilds and buy new iron or maganese bronze but then you do this you have to watch the way you drive the out the EX side is in water and need to go out thru the head out the vavle cover side there a step on the vavle guides run it out thru the deck side i you will junk the head . if you go this way there is a chance the seat run out could be great. gm did finsh machine out the guides s when press in and have seen the guid hole off to one side. this is not to big of a deal if your going to cut out for bigger valves .i have done them both way is core ream them and put a new 502 OD wall guides in or drive an full new guides in the core drill/ream this need to be done with the right tools and a seat guide machine or a thin wall linner you can buy a kit to do them with a thin wall linners and is a fast to do this way but i like the 502 wall solid guides to put in .this help if the valve guide hole is way off you center up on the guide hole not the od of the valve guides .even if you go over size on them you would need a ream and should run the ream with a gear box on a hand drill all this stuff is very $$ less your going to do more then on e set of heads hard to say how bad the guide hole is it could be hone with a brm ball hone but i would clean the hole out then run a ream thru first then with with the reamer to keep if from getting bell mouth and your going to need a valve job or that least a touch up on the one valve that was stuck