Hi fellows. I have a pair of 690 heads that have differant valve guide bosses. The one is smaller diameter than the other and this concerns me. It looks weak when comparing them and may cause a problem. If the smaller boss has been modified would this have been for double springs or is this stock from GM? Can I use this head as it is or is it going to need to be reinforced? Brazing a coller over the boss would be easy to do. I have included pics of both heads. Your help and opinion would be greatly appreciated.
