Those guides need special tools and skills as far as honing. I picked up a good (cosmetic) head for my own 1971 Fastback off US eBay and had it sent to Jim Comstock who fitted the above along aluminium bronze inserts in the exhaust ports and 3/8" stud threads in the deck. His rates are very good, quality top shelf. He then sent the head to me in Australia.
Can of worms. You just can't pull in a new guide. Guide must be reamed/honed straight. not with a dingle berry hone. Seat needs to be recut because the guide ends up in a different spot. That requires valve to be refaced. how about the valve stem wear. so is the shade tree patch and go or do it correct. Bill Frease Youngstown 330-360-7921 Rodi's Winder Ga. 770-867-1676 Leo Goff 901-757-1009 & Dave Comeau BB Norton moderator These fellows been at this awhile check with them Your bike your $$$$$$