I once mentioned to my Mother, that Canada was selling their P-51s with a spare engine for $1,000 in the early 60s, she just said, "who had a spare thousand dollars lying around!"
That $1,000 in 1960 would be $8,000 in 2015 (CPI Inflation Calculator).
I have uploaded some pretty cool videos...complete with various Mustangs, and one with a .50 cal Browning installation doing target practice. Check out the recoil of the Mustang as those rounds leave the barrels!