Hello everybody,

I am attempting to install new 4” wood flooring, but have a question about the subfloor currently in my home. We have 1x8” planks installed diagonally across joists, but from time to time there is more than the suggested 1/8” separation between subfloor planks. Is a gap of about 1 inch too wide for installing wood floor directly over subfloor planks?

Planks are stiffer than plywood. You will get plenty of support even with larger than narrow gaps unless you are installing less than half inch engineered.
I will always add another fastener between the usual two fasteners for each time the sub-floor crosses a joist.
For extra security you could add strips of sheet metal nailed to the edges of the gaps along the planks. Sheet metal is very strong.