The only thing I have found describing the performance of the F8F that correspond to the numbers that you give relate to the F8F-2. Nothing I have found on the -1, which would be the one (if one was ever introduced) that would be here, indicates the type of climb you are describing.
Don't get me wrong, I think it is a great performer. Hell, I may be wrong (probably am). However, everything I have seen states that it is not as great as some make it out to be. Like I said above, I would love to have it here, but I also think there are other, more significant planes that should and need to be added first.