The value of a Javelin in “good” condition is right around $22,000. Of course, this is for cars equipped with the 390. Special cars cars, like the Big Bad, can add about 25% more. Sadly, it is on a steady decline in value from recent 5-year highs of $26,000.
The Mustang, on the other hand, holds value very well. The average muscle car enthusiast won’t be able to afford a Boss 429 or 428 Cobra Jet. A Boss 429 will cost about $200,000 in good condition which is a dramatic increase in value from their 5-year lows of $130,000. Remember there were very few of them built, and will never be worthless, except after the zombie apocalypse.
If you’ve had your eyes on a regular, plain Jane Mustang coupe with a run-of-the-mill 302, you’d be looking at about $14,000, which is up from recent lows of about $9,000.
Availability of parts:
This is important because if there aren’t any parts available, you’ll give yourself a heart attack just trying to source what you need. The Mustang production numbers for 1970 were just over 190,000, so you won’t have many issues trying to find parts for it. In case you were wondering, there were only 499 Boss 429s built that year, so they are sparse and cost a fortune to buy.
The Javelin on the other hand, wasn’t as popular of a ride. Fewer than 35,000 were built for model year 1970 (including the shorter AMX), so you’d have a harder time finding parts.