You can buy a thermostat housing with a threaded port already in it. .
https://www.cjponyparts.com/thermostat-housing-with-threaded-port-260-289-302-351w-1965-1973/p/TH16/
Funny, my parents had a '78 Country Squire wagon in Champagne Gold and it looked good with all the woodgrain to accent it. Never thought this color fit a Mustang until I saw a '69 Mach with all the black out to compliment it.
Very nice work.
Those inner headlight buckets should be "blacked out" like the factory did … they really stand out on lighter color cars and now would be the time before you get any further.
I did it on my Calypso Coral car after the fact back in the 80's because I hated how that orange glowed out of those corners and later found out it was actually something the factory did too.
Doug
Exciting day yesterday as we stopped by and got a first look at the car after paint on the way to drop my oldest son off at college. WOW! What a nice job by Richard Vickers and his guys at Dark Forest. Get to bring it home next week.
I have just done my 65FB, so what I do is put a line of masking tape just outside the area that is the gasket line before the glue is applied, this prevents you getting glue marks on your paint outside the gasket line.