Keeping things pretty vague and nebulous is fine - like I said, it's fine to leave Cap (in the comics, he's already exceeded this a bit in the movies) somewhere indeterminate between Olympic weightlifting and being able to bench press or toss even a compact car. It's a guideline, not some hard and fast number... but by that same token, you don't want to suddenly have him tossing cars across a city block, at least not without an explicit boost within the context of the story, lest you lose your readers' willing suspension of disbelief.