I was just curious, what are the advantages/disadvantages (if any) to installing a bigger battery than the stock one? Only reason Im asking is because I can get a new one for free but its bigger than the one recommended.
When you say "bigger", if you mean in actual dimensions I would be VERY careful.
240 and 260's had the battery mounted to the rear of the engine compartment on the right hand side, right below the side access panel. A stock battery comes very very close to touching the underside of the fender, and in order to avoid that, requires a hold down strap / frame. If it were to bounce and make contact with the fender...instant short and possible electrical damage as well as fire. Changing the battery dimension in height would almost guarantee that the posts would touch metal someplace, and don't forget that some of the battery cables are almost too short to begin with.
If by bigger you are referring to it's capacity in cold cranking amps, I don't think anyone will argue, go for it. The battery voltage is still going to be 12 volts, and the current draw from it is going to be defined by your car and it's components and not by what the battery can do, Additional cold cranking amps just means that the battery will have a higher reserve.
escanlon is absolutely correct to warn you about the battery-inspection lid tight clearance. It is tight. If the battery you want to install is no taller than your original battery, go for it.
You might also be able to accommodate a slightly taller battery by removing the stock batter holder and installing an aftermarket part. If you could find a big battery with side mounts, that would be great -- but you'd have to re-do your cable connectors.
It is bigger in dimensions, it never crossed my mind that it might hit the inspection lid, I tried it out earlier to see if it would even fit, it barely fit with the battery hold down around it, but now I think Ill go ahead and get a correct size battery.
is the Interstate Megaton 24F. (1000 CA, 850 CCA)
the cool thing about it is the posts are reversed, meaning the pos is by the motor and the neg is under the inspection lid/frame support. Be sure to get a battery hold down frame from MSA... The do work!