Does the Volvo used a pressurized coolant system because I was looking at the coolant tank and it has a pressure relief cap? I want to change out the tank and I'm not sure if I need one with a pressure radiator cap. Thanks

You want a pressurized system. The addition of pressure allows the boiling point to rise from 212F to about 240F, so you are not boiling off coolant in the hotter parts of the engine.

The plastic expansion overflow bottles are not expensive and I am dumbfounded as to why you want to use a corrosive metal can. That would also not allow you to see the fluid level.

Klaus
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Praying for Cynthia Amendt, heaven bound

Starting in 1967 they had a plastic bottle connected to an elbow on top of the radiator.
It has a 7 psi pressure cap on it.
Before that they still used a pressure cap but did not have an overflow bottle.
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George Downs, Bartlesville, Heart of the USA!

Is it poss to replace the tank without using a pressure cap??

It's more of a bottle than a tank.
It's a good thing - keeps you from losing coolant.
Remember that the bigger the difference between the coolant temp and atmospheric temp,
the more heat you transfer.
If you have a leak in the system you can leave the cap loose until you fix the leak.
But that is a temporary stopgap that will only reduce, not eliminate the coolant loss.
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George Downs, Bartlesville, Heart of the USA!

I just want to remove the plastic tank and replace it with a metal catch can. I've already installed a 140 radiator which is much more efficient then the 122 with a slim electric fan. Thanks for all the info.

The same bottle is used on the 140.
If you don't use a closed system you will continually lose coolant, so you might as well
use it the way it was designed.
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George Downs, Bartlesville, Heart of the USA!

Regardless of what rad, no bottle or with bottle, it still has to work as a pressurised system. If you have a 140 rad, it's set up to use a bottle. The rad has a fixed seal that is only disturbed for filling. With the system properly bled and the bottle filled to the midpoint mark, there is enough space for the water to expand into as it heats up. As the water cools down when you park the level drops again. This means that the rad stays full all the time and coolant should't need topping up. Like that, the cooling system works as designed and at full efficiency. Use a 10lb cap on the bottle. Officially a 4lb cap on the non bottle rad but 7lb often used.
A catch tank isn't needed on a proper system even though you might see one on a comp car just to comply with the rules.