In order for the year to be 360 days long the day has to be longer than it is now in the ratio 365.2421897/360 = 1.01456164:1 = 1.456164% larger. In other words rather than being 24 hours long it would be around 24.35 hours long. How could this have been the case? Well when an ice skater spreads her arms out she rotates more slowly and when she draws them in she rotates more quickly. If the earth spread out a bit and got fatter at the equator and flatter from pole to pole (as if someone was treading on a basketball) then it would rotate more slowly and so the day would last longer. But the earth is actually fat at the equator and squashed at the pole due to centrifugal force and the liquid nature of the earth under its crust. So if the planet were hotter then it would be more liquid and so the centrifugal force arising from its rotation would cause it to expand and be fatter at the equator. Now before the flood this was the case. The flood dumped a load of water from the atmosphere onto the crust of the earth which would have cooled the earth down and therefore stiffened it up and reduced the bulging effect of centrifugal force. So we propose that prior to the flood the circumference of the earth was larger than it is today.
A geographical mile (which is the distance on the equator traced out by one second of arc which is one 60th of a minute of arc which is one 60th of a degree of arc which is on 360th of a circle) would in fact be almost precisely 6,000 feet long rather than the present 6,087.253 feet long if the earth was indeed 1.456164% larger in circumference and therefore the day was 24.35 hours long and the year had 360 days in it. This is because 6,087.253 is 1.45421% larger than 6,000.
This all works because the circumference of the earth is linearly related to the period of its rotation around its axis for small variations from the present 24 hour day period in order that angular momentum is preserved. For if we keep the velocity of its surface the same then for small variations in day length we preserve angular momentum which is the integral of mass x velocity for each particle of the planet. So to increase the day by 1.456164% we increase the circumference of the earth by the same amount.
So we propose that the flood waters cooled the surface of the planet down by such an amount that it stiffened up to such an extent that the centrifugal force of its own rotation caused it to bulge by 1.45% less. Hence it spun 1.45% faster. Hence the days became 1.45% shorter. Hence the year contained 1.45% more days. It increased from 360 days to the present 365.2421897.
This is an interesting possibility, But when the earth is moved from her place…Isaiah 13:13, then we will return to 360 day years.