Good question and I wondered that myself last night.
Looking up rear discs on Rockauto they do seem to be vented. It does give me a thickness of 26mn so I can check that with what I have, perhaps wrong ones are in there.
Done a few emergency stops on the drive way. Checked for any brake leaks. We are good to go.
A little drive around the block at low speed. Was some noises like pads rubbing on the disks. That may just clear with driving. There was some smoke under the bonnet, like oil seeping out of the rocker cover(not sure).
Darren recommnended some Stop leak to revice old gaskets. https://rislone.com/international/wales/
wouldn't be surprised if rocker cover gaskets need to be replaced as been siting for so long . the link above for the seal restore wont do rocker cover gaskets but will help will valve stem steals other brands of that stuff are available,
do you know if rocker cover gaskets are rubber cork or silicone type???
Oil difficult to fill up as soon much stuff around the hole. This is after removing some stuff already.
I have this funnel but the end it around 38mm need 28mm to get it in the oil filler hole.
Whipped up a design for a 28mm funnel. Started printing already
The scraping noise from the wheels verified to be rusty disks, can cause it by rotating by hand. Bearings are good. The rust will wear off with driving. Only part of the disk has rust now. So it is getting better.
Filled it up with some new antifreeze recommended by guys in the car club. It's pre mixed. Radiator full and bottom pipe full. Need to run it up, but first need to put oil in. New funnel ready at midnight.