Should I pay down principal for long term gains?

[Levi Klein]

Im finishing up a flip and will have 150k after its sold. should i put this money toward my primary residence mortgage and eliminate 18yrs interest essentially doubling my money? i see this being similar to Brrrr. My wife will not let me sell and move so this is our "forever home" i would immediately up my HELOC to 230k from 80k to have these funds available within 60days for other investments. conventional financing methods are not available to me because of a foreclosure and my HELOC is cheaper than private money. This seems to make a lot of sense to me. I've pretty much made my mind up to do this but would love to see a better use of my dollars if any one has an idea. Any input would br great! thanks BP