C2 427/425 Valve Seals and Guides

[Bill W.]

Re: DO NOT replace the guides

Clem I have an extra set of 65 396 heads. a couple of the valve stem giudes are cracked from valves being knocked out of the head when the valve tip was worn. what should be done to repair these ?....Bill

[Clem Z.]

Re: this is another reason not to replace the guid

i have been out of the business for over 10 years and back then guide sleeves were a lot cheaper than new valves.

[Clem Z.]

Re: DO NOT replace the guides

are they cracked or just gouged? if they are truly cracked you must replace them and hope the seat in the head will not be too far off center. if the seats are too far off center you can install a new seat insert even in cast iron heads because there is plenty of room to do this without any problems. you could also install the next larger diameter valve head size to help center up the seat. we used to install hot rolled steel seat inserts in cast iron heads exhaust to be able to form a venturi effect like used in aluminum heads which was good for 15 HP

[Mark #28455]

salvage from a scrap head

If you can use a dial indicator, you can measure which side of the original guide is high and by how much (they're not concentric). Grab a late model scrap head (the "peanut port" heads sometimes crack through the exhaust area) and measure those guides to find how much out of concentricity they are. Then pick the closest one, drive your original out (after noting the high side) and drive in the new one with the high side in the same orientation. If you're lucky, the new guide will be close enough to match up with just a valve job.
Mark