Hey, I don't know everything. Some say I know a LOT less than that!

Re. the antifreeze, read the charts on the backs of the products. They show the protection at different concentrations.

Pay attention to actual concentration in the block. Even the best draining that I know seems to leave about a quart in there. And it looks like the stuff in the reservoir only goes down if coolant is removed. So if I really cared about the concentration, I'd look up the exact capacity (about 10 qt) then put in 5 or 6 qt of antifreeze depending on the concentration wanted, then add water to fill.

A friend of mine put in a gallon, added 4 qt. water, found it was full, and he's done! My guess is that he has 4 qt antifreeze and 6 qt water in there, since it holds 10 qt., and we'd been flushing the motor with water from a hose.

There's a nice brass block drain low on cyl. 3 + 4, exhaust side. A good place to get a sample of the stuff that's inside. Make your motor rebuilder clean the drain assembly of any old crud, not just screw it back on. When using the drain, a 3/8" pvc hose will slip on and carry the stuff to a nice jug. Use a 2.5 gal. water jug, turned on its side with a hole in a top corner. Works great even if the car is on the ground.

Tranny -
Standard tranny?? They take ATF?? I never had a Volvo stick. Anyway, lots of guys swear by synthetics. Probably a good idea. I never explored that area.

If auto tranny, while the motor is out, check the tranny rear tailhousing bushing and rubber seal. That's where they usually leak, when the bushing wears. About $200 if you have to tear stuff apart to get there, but you're substantially disassembled already.
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Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute.