GM's 1967 Custom -- a pretty close match to my dad's first truck. Image source: General Motors.

Ford Mustang, or Chevy Camaro? F-150, or Silverado? Ford (NYSE:F) stock, or General Motors (NYSE:GM) stock?

Everyone who's ever driven a car has a favorite. Some have more than one. For me, it's a toss-up between my trusty, rusty 1982 Datsun 310, which gave me 35 miles per gallon way back when -- beating today's CAFE standards by 1 mpg and 34 years -- and Dad's 1969 GMC Custom pickup. That ol' truck, which we named "Babe, the big blue ox," was the first vehicle I ever drove -- and it got approximately 8 gallons to the mile.

Some fans go beyond playing favorites and can get downright inventive thinking up catcalls  for the competition. For example, GM fans have been known to deride Ford's brand as "Fast Only Rolling Downhill," while Ford backers insist that Chevrolet really stands for "Constantly Having Every Vehicle Recalled Over Lousy Engineering Techniques."

Clearly, Ford fans don't have a lot of respect for GM -- and vice versa. At the same time, it seems that investors don't have a whole lot of respect for either Ford or GM. Last week, Ford confirmed that after six years of nonstop growth, car industry sales have finally peaked and begun to fall -- a fall Ford expects to continue through 2017.

Result: Ford Motor stock now sells for a price-to-earnings ratio of less than 6, while a share of GM will set you back a mere four times earnings. But for bargain hunting buyers, that might spell opportunity. Today, we're going to stack up Ford stock, and GM stock, side by side -- and see if we can pick a winner.

Ford Motor Co.

Let's roll Ford down the hill first. Valued at $47.5 billion, Ford Motor Co. earned a whopping $8.5 billion in net profit over the past year and generated $13.5 billion in positive free cash flow, giving the stock a P/E ratio of just 5.6.

Meanwhile, despite management's warnings about an impending sales decline, S&P Global Market Intelligence reports that analysts who follow Ford stock are still looking for 15% annualized earnings growth from Ford over the next five years. The resulting PEG ratio at Ford -- a mere 0.4 -- seems exceedingly cheap.

To top it all off, Ford is paying a whopping 4.7% dividend yield today. And according to the Fool's resident car guy, John Rosevear, this is a dividend that Ford can easily maintain even in the face of a sales slump, because Ford has a good $27.2 billion in cash stored up from the good days -- money that it can use to pay the dividend for as long as needed.

General Motors

So how does that compare to General Motors stock? Believe it or not, GM actually looks even cheaper than Ford.

Valued at $46.8 billion in market cap, GM is very similar in size to Ford. But the past year has seen GM produce $12.4 billion in profit -- about 45% more than Ford. As a result, GM stock now sells for the low, low price of just 3.8 times trailing earnings.

Analysts polled by S&P Global market Intelligence see GM growing slower than Ford, but only by a skosh -- 14.8% annualized over the next five years, versus Ford's 15% growth rate. Assuming they're right about that, GM's PEG ratio works out to a nigh-on ridiculous number: just 0.25. GM's dividend yield of 4.8%, moreover, just adds to the stock's attractiveness.

So which stock is the better buy?

I must admit that I'm really torn here. Mathematically speaking, GM stock at a price-to-earnings-to-growth rate ratio of just 0.25, and paying a 4.8% dividend, appears marginally cheaper than Ford stock at 0.4 and 4.7%. But honestly, this almost looks like a distinction without a difference.

If analyst estimates are to be believed, GM stock is likely to experience only a minor decline in earnings this year versus 2015 and then next, before bouncing right back to hit even higher highs. Ford, say the analysts, will see earnings dip in 2016 but bounce back as soon as 2017. If these predictions come anywhere close to being right, then the prices investors are being charged to own Ford and GM stock today are very close to ridiculously cheap, and basically justified by the stocks' dividend yields alone.

When you get right down to it, then, if you ask me whether Ford or GM is the "better buy," my answer is that they're both so cheap right now, you can't go far wrong by investing in either one.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.