radiator cap ---maybe a dumb question ?? but, here's the story ...

- 1987 2wd runs like a Swiss watch
- have zero cooling system issues/ problems/ leaks, or anything...including today, idling 10 minutes in 95 degree heat...

the radiator cap is from my "burned-down" ex-1986 van
it works perfectly
it's ugly and tarnished, however, from the fire

Can I use a " 1.0" nippondenso cap from my Sienna in place or the " 0.9" ND cap that is on there now ???

it's been in use in the Sienna for 15 years, so, I assume it's a bit weaker than its "new" rating...
am I asking for trouble ? will there be too much pressure ? or, will it be about equal to my "2-year old 0.9 cap" that I've had on there now ?