Classic/Antique Car Repair: 55 Ford F100 battery, f100 engine, ford f100

Question
Hi,
I would like to change the 6 volt battery of my 55' Ford F100 (engine 239-V8) but I do not know what is the exact type of battery I need to buy. I do not have the owner's manual and I think I have to be careful about the amperes. Can you tell me what are the important informations/details I need to know before buying one.

Answer
There is nothing to worry about with respect to electrical specifications - any 6 volt automotive type battery will work just fine in your truck.

However, there were special batteries made for Ford, the only difference being in the locations of the positive and negative  terminal posts on the top of the case, and the physical size of the battery.  The only consequence of buying a different battery is that your cables may be too short to reach the terminals, meaning you would also have to buy new cables.  Of course the battery must be small enough to fit in the assigned space, but it may be smaller and still work fine, it just can not be too large for the holder.

If you are interested in precise authentic appearance of the battery, you need to contact one of the vendors who specialize in reproduction batteries for any old car. These are quite expensive, but they are neccessary if you are going to be showing the truck in a judged concours.  

The original battery for your truck was a FORD branded battery with a BCA number of G2NPP and an ampere-hour rating of 118.  In the modern rating system that would equate to a CCA rating of 660 Amperes.   The size of the original battery was 10 1/4" by 5 1/2" by 9" high.  One vendor for this battery is the Antique Auto Battery company, which you can contact at www.antiqueautobattery.com.

If exact authenticity is not your concern, all you need to do is to measure the size of the battery holder (the maximum "footprint" it can hold) and the vertical clearance into which the new battery must fit.  Other than that there is no reason to worry about the amperage rating.  Modern batteries are not rated with the same system as they were in the era of your truck anyway, so you would not have any luck finding the exact same specification anyway.  Just buy the highest rating CCA (Cold Cranking Ampere rating) battery you can find that will fit into the holder.

As you are probably aware, your truck was designed to be operated with the positive post of the battery connected to ground - the negative post is the "hot" terminal.  This is the reverse of modern vehicles - so you must be very sure to  advise anyone who is working on it that it is a "positive ground" system - most mechanics have never seen such a vehicle, even though they were once more common than the current standard, which is negative ground.  This does not affect the battery itself, it doesn't care. It only affects which cable is attached to which post on the battery.

I hope this is clear enough - if not, please post a follow up question and I'll try again!

Dick