You can put any motor in any vehicle as long as you can gear correctly. If I had a 5,000:1 gear ratio in my regular size SUV my tekin motor could easily power it and it would go 1 mph. For a 14.5 truck you would have no problem with a 30:1 ratio and the rpm required to get up to the speed you want.
Check out my custom converted 8ight:
Sub 7lb, lowest CG of any 1/8 buggy