Grounded the IVR and cleaned the threads out of the intake where the sending unit screws in and also made sure the motor to body ground was clean and the gauge still wants to start up from cold,the cooling system in the 351 was acting strange so I need to get a Y block rebuilt soon.  The coolant level was going up and down and was doing it hard enough to vibrate the car but did not overheat,with the radiator cap on I could feel it in the hoses and at idle the temp would go up to slightly over 200 so I replaced the thermostat and everything seemed normal again and after a 30 mile ride did not act strange again but will need to keep a watch on it.

Butchering up everything I can get my hands on in Dayton Ohio

I think I got the correct sending unit and will check the ground on the IVR when it quits raining as I will have to pull the 55 out of the garage so I can open the doors enough to get under the dash.

Butchering up everything I can get my hands on in Dayton Ohio

The IVR should be grounded where the mounting screw goes.Do you have the correct sending unit for the gauge you are using?They are all slightly different for a particular year.

  

Took it for a ride today and the gauge is wanting to start at 1/3 up again but when warmed up runs about 3/4 which it did before the conversion to 12 volts,what will cause the gauge to do that and maybe I will get another IVR but the gas gauge is working just fine.  Should those IVRs be grounded and will check it tomorrow,at least the gauge is not pegged all the way to hot when warmed up but its still not right.

Butchering up everything I can get my hands on in Dayton Ohio

Hello Jeff! The only Ford gauges that took a full 12 volts were 1956 only.That voltage regulator you have is basically a set of points that open and close.The average voltage out is 6.They used those on many vehicles during the 60's.Very handy if you are converting a vehicle from 6 to 12 volts.  

  

It's always good when you find a fix to something especially if it's been whippin' your butt for a long time.

Doing Fords for 45 years. '56 Customline Victoria

E.J. in Havana FL

It probably would of been easier to remove the whole cluster but I managed to get it out under the dash,someone told me I did not need a resister and the gauge would handle 12 volts but I fried it so today I put in the NOS gauge.  It would start out cold with the gauge about 1/3 up and would peg all the way over to hot and put up with it for over 3 years,after the gauge was installed it pegged hot and I remember I picked up a new sending unit last year and now it works like it should.  I am glad I did not have the gas gauge hooked up at the time or I would of needed a new gas gauge too,the gauges are being controlled with a instrument voltage regulator from a 69 truck.

Butchering up everything I can get my hands on in Dayton Ohio