The Stovebolt Site Forums The Shop Area Engine Shop Battery size?

I have recently aquired a 1949 3100 with what I believe to be a 1954 235 engine in it. The block is marked casting 3835911 by the fuel pump with F54Z stamped next to the distributor, and the head is casting 3835913.

I am ready to spin the engine after an unknown time of it sitting unused. The engine spins by hand with the plugs out, and all the valves move when I turn it by hand.

It looks like it was converted to 12 volts at some point. Generator is marked 12V and there is an ignition ballast resistor?? mounted on the firewall (a white rectangular ceramic looking thing with a wire screwed to each end). There is no battery right now.

What size battery should I buy?

Can I just use jumper cables from my daily driver 1988 K1500 to see if it will spin before I buy a new battery? How can I know for sure if its negative ground?

Thanks!!!

Chevy had negative ground, GMC was positive. If your jumper cables are heavy enough you should be able to turn the engine over. Do not crank for more than about 15 seconds continuous to avoid overheating the cables and/or starter. If the generator is working, you can disconnect the jumper cables and the engine will continue to run, don't try this with an alternator.

Battery size, iirc is a 24. To be sure, measure the battery box and buy one that will fit in the hole. Don't forget about the height, you don't want the cover shorting out the posts.

Hi,
I have a 1948 Chevy 1/2 ton with a 55 235 and 12V generator. All the Chevy's were negative ground, you need the ballast resistor to keep from burning up the points. Ensure it has a 12V coil. If it turns by hand then it should be alright, I just fired up a 60's 250 after sitting for over 2 years after changing the oil and pouring some gas down the carb. SHe fired right up. I have seen guys fire up 235's after sitting for unknown years by pull-starting without knowing what You know.... Not recommended... Keep a close eye on oil pressure when you do start it, and you might want to pour some oil accross the valve train prior to starting it. I als like to put a little marvel mystery oil in the cylinders when the plugs are put to help seal and clean out the rings. Plan on replacing the fuel pump soon as they tend to dry out when sitting for a long time. I have an old Allis Chalmers tractor that had not run in over 25 years and after tinkering for a week, and a new condenser and a clean out of the carb and fuel lines, she fired up, albeit with quite a bit of smoke, but the rings started to seat after about an hour of running. The oil pressure is a little low, but most likely due to it is realitively wore out.
Hope this helps out,
Garry