1969 Boss 429 Temperature

[paparazzi]

Has anyone ever confirmed the actual water temperature on a 1969 Boss 429 when the gauge sits squarely on the "H"? I am just wondering what the actual temp should be when gauge is on "H"? I am new to this car and  have tried changing the sensor and now trying to confirm if the gauge is bad.
Thanks, Bob

[C6ZZGT]

You should be checking the ohms of the sender .............

[shelbydoug]

It should also be mentioned that ONLY the AUTOLITE or MOTORCRAFT senders are accurate. ALL the aftermarket senders are calibrated wrong and read too high. They are both obsolete and command significant premiums now, when you can still find them.

Measuring the OHM's of all of them is the only way to calibrate them.

[Royce Peterson]

Even some of the Motorcraft senders are way out of specs. Be sure to get one with the red insulator around the center stud. Anything else will be a waste of your time and money. Autolite or early Motorcraft work.

[paparazzi]

Thanks for all of your helpful comments. Would this apply to 428 Cobra Jets also? I assume the gauges are all the same? Any suggestions on where I might find the correct sending unit?

[shelbydoug]

Post a wanted ad. They are obsolete and not a common everyday occurrence. Relatively expensive as well compared to other aftermarket senders.

You're going to need a little luck on this one.

[paparazzi]

Thanks again shelbydoug. Just to help with my post, would this be the same sending unit as used in a 69 428 Cobra Jat? If the Boss 429 uses the same gauge then should the sending unit be the same? Thanks, Bob

[shelbydoug]

I believe that it is the same.

Just post a wanted ad here. I suspect that you will receive some offers.

[paparazzi]

Thanks to everyone for help with the Boss 429 temperature sending unit issue. Especially Shelbydoug and Royce Peterson. I managed to source an OEM part (still seems weird to me I couldn't find an after market that is not correctly calibrated) and it solved the problem. The car will not be driven a lot but at least now I know if the temp gauge gets up to "H" I have a problem. I just keep learning!

[shelbydoug]

Thanks to everyone for help with the Boss 429 temperature sending unit issue. Especially Shelbydoug and Royce Peterson. I managed to source an OEM part (still seems weird to me I couldn't find an after market that is not correctly calibrated) and it solved the problem. The car will not be driven a lot but at least now I know if the temp gauge gets up to "H" I have a problem. I just keep learning!

It is very strange. Even stranger that the aftermarket manufacturers claim that theirs are correct?

I had to learn the hard way just like you just have.

I'm glad that I could help and it worked out. It's crazy that anyone needs to go find one for $100 on something that should only cost $20.

These days you just can't take anything for granted. You have to check everything yourself which actually adds to your growing knowledge base. 
as a result NO ONE touches my cars. If I get killed in it then it is my fault not someone else's incompetence.

[paparazzi]

FYI--my 69 GT with 428 and my 68 GT500KR with 428 also have the sending units with the red insulator just in case anyone ever runs into this on one of those.

[shelbydoug]

The red insulator is intended for quick identification of the correct sender since they all look alike at assembly time.

[Royce Peterson]

Thanks to everyone for help with the Boss 429 temperature sending unit issue. Especially Shelbydoug and Royce Peterson. I managed to source an OEM part (still seems weird to me I couldn't find an after market that is not correctly calibrated) and it solved the problem. The car will not be driven a lot but at least now I know if the temp gauge gets up to "H" I have a problem. I just keep learning!

My experience as well.

[deathsled]

Is this general rule across the board including 289 and 302 engines?

[shelbymann1970]

FYI:  Bob got the correct sending unit. Installed it and his temp gauge is working properly now.