People must be doing something seriously wrong if they are only getting 4 gallons out of any engine... I've been getting no less than 10 gallons from any engine that i've owned... V-spec's take take about 1-2 gallons for the metal to metal pinch to dissappear and this is when i've found they perform the best!

If a V-spec is carefully broken in, you should get 8-10 gallons with no more than a rod and a front bearing

This is just my opinion based on my experience