I can well understand your attachment to the frame; however trying to update old frames is a good way of ending up with an expensive compromise, that doesn't work particularly well and looks a bastard.
You've already got a 27" front wheel and fixed rears are available on Ebay for sub-£50: bang, you've got a decent beater/pub/Winter bike.
You could then buy a modern threadless frameset and build that up for "Sunday best".
I can tell you from bitter experience that this will be cheaper, less frustrating and you will have two bikes that perform well and look boss.
I can well understand your attachment to the frame; however trying to update old frames is a good way of ending up with an expensive compromise, that doesn't work particularly well and looks a bastard.
You've already got a 27" front wheel and fixed rears are available on Ebay for sub-£50: bang, you've got a decent beater/pub/Winter bike.
You could then buy a modern threadless frameset and build that up for "Sunday best".
I can tell you from bitter experience that this will be cheaper, less frustrating and you will have two bikes that perform well and look boss.