Gas2.org has posted an article about Engine RePower, a site which advocates swapping an engine instead of buying a new car to reduce the amount of energy used to recycle your old car (because of blown engine). I do not know enough about the recycling procedures for current cars so I am unable to say with any accuracy how much energy is saved. But it got me thinking, we have seen many older cars from the 60’s, 70’s, and 80’s receive a modern swap. Many engines in those periods had great horsepower but they cared very little on gas consumption. Engines today do a much better job of producing horsepower using less gas. Then we could get into the whole “most” swaps deal with a smaller car and this sheds weight which requires less engine for the same performance level. I guess in the end it all depends on your perspective.