Ethical question about a gift from a friend

I normally am the last person on Earth to ask internet forums for their opinions on things like this, but I'm legitimately on the fence about what to do and I want to get as many opinions as possible.

A while back, a friend of mine allowed me to have an old junker vehicle they owned, free of charge, if I came with my truck and trailered it out of their yard. Since I'm a decent car mechanic and I have done vehicle restorations in the past, I agreed and came and got it in the middle of winter. It was a considerable task to extract it and get it on the trailer and home to my garage.

I've worked on it and done some improvements, and it runs and drives (although not terribly well). Problem is this: I'm kind of in a tight spot cash-wise right now and I have some expenses I need to cover in short order. This vehicle is one thing I own that I can sell quickly and make some cash. But I feel conflicted about whether it'd be right to turn around and sell it for profit when I was given it for free, with the expectation I would restore it and give it a second life. I've done some work on it, but not enough to feel like I've necessarily earned the right to 'flip' it.

What say you? Should I keep it and restore it as planned, or am I in the right to sell it since it is now my property?