View Full Version : HELP: How to change a 6 Volt 51 Flathead to a 12 Volt

04-14-2007, 04:55 PM
First off, if there is a post on this exact subject please shoot it to me. I looked, but didn't find what I was looking for.

I would like to know a guess on what it cost to change a 1951 Ford Flathead 8 from a 6 volt to a 12 volt. Also, how is it done? I appreciate your help all!!!!:D

04-14-2007, 05:06 PM
I'm at work right now but when I get home I'll post a link to a page that has good info on the conversion.

04-14-2007, 05:19 PM
I appreciate it!!!

04-14-2007, 05:32 PM
Try here:

04-14-2007, 05:53 PM
Sinner, since my ride is all ready 12 volt system, all I need to purchase is a alternator and Ignition, does that sound right?

04-14-2007, 07:40 PM
I thought it was a 6volt and you wanted to go to a 12volt ????

On my chev, I stuck a one wire alt in there and changed over the bulbs and put a battery in it. Im still using the stock 6 volt starter and stock ignition switch...with no problems at all...Not so sure about your flatty....

04-14-2007, 08:09 PM
Very easy especially if you already have a 12 volt system on the car. You'll only need a new coil and a 1 wire alternator. I use a Mallory unilite distributor on my 51 Merc and have no problems. Most of the supply houses like Hot Rod and Custom supply sell a little book on changing systems over to 12 volt. Cost a few bucks and has alot of information.
Here is a link to Speedway motors and the book:,385_The-Official-12-Volt-Conversion-Guide.html

04-14-2007, 08:18 PM
OH, And your 6 volt starter on the Flathead will work fine on a 12 volt system. No need to change or convert anything there.
If you are running an original tranny with an overdrive then the solenoid will have to be converted to 12.

I go pogo
04-14-2007, 08:22 PM
I use a stock 6 volt starter and distributor with a ballast resister in the wire to the coil.

04-14-2007, 09:16 PM
This is great information and really appreciate it. Sinner here is alittle more in detail of what I meant. I built a 31 Ford making sure all components ran on a 12 Volt system. I just purchased a Flat head off a guy who was still running the 6 volt system. Anyway, it sounds like I do not need much at all so I should be on my way in a few weeks. Thanks guys!!!!!!!

04-15-2007, 08:18 AM
dosn't look like you need it any more but here's a 12v conversion link if anyone needs it.

04-15-2007, 08:21 AM
Cool's a fairly easy to do conversion...good luck

05-26-2007, 07:08 PM
Thanks again

09-20-2007, 01:10 PM
1 question on this post. What should I do with a stock voltage regulator on a 6 volt system? DO I jumper or splice any wires and shitcan it? Or just put a 12 volt in it and use the gm internal reg and external regulator? I am converting my 6 volt 53 ford to 12 volt. thanks for search option!