Re: fan shroud
A 69 SBC shroud will give you the correct placement of the fan inside the shroud depth wise and will work assuming you have a stock fan clutch and fan and a non AC radiato (21")r. If you have your original shroud, it will work on a 21" radiator, the fan will just be about an inch deeper into the shroud.
The AC radiators for 67/68 are wider (23" instead of 21") and you would need to use a 67/68 AC shroud with it. As iwth an original shroud, this set up will put the fan about an inch deeper into the shroud.
69 Pace Car and 69 Hard top