Any car battery that will hold some charge. Something off a 4cyl Jap car that is not quite enough to start reliably in winter will be thrown out and a charge from a Swallow etc will have it plenty good enough.
But if you can find one from a large 4WD, even better.
If you go to any mechanic and explain what it is for they will have one that they replaced only to save the owner possible heartache but it is still 90% good enough for a car (so plenty for ur starter box)
Mehcanics pay money to get rid of batteries and are more than happy for you to take one (or four!)