Realizing that 53 year old guages were not that accurate to begin with and may even be less now, I have a question:
I have a 70 351C with what appears to be the original water temp sender, a Flow-Kooler Robert Shaw 180 high flow thermostat (with brass restrictor "ring"), a replacement (NPD) guage cluster harness, and am drawing power for a Holley with electric choke from the temp guage power wire.
Runs great, no signs of overheating regardless of ambient temp., etc. I generally drive it for 30-60 mins at a time max.
My temp guage needle usually sits on the "C", or slightly past., which I think is a bit low. I let the car idle for about 25-30 mins once and the needle moved almost to half way between "C" and "H"
I think the guage is reading low and am concerned it may be because of the power draw. Do I have a problem, or am I chasing something that isn't there? :) Thanks!
Sounds fine.
I agree with Royce in that the there is no power drop in the gauge feed harness causing a mis reading gauge.
the repo water temp senders (or at least some of them are as much as 20 off) and there are many different ones and the repo radiators dont have correct cores depending on if factory a/c and engine size from what i been seeing.
Sounds fine. My 428 car runs at the half mark, even in Texas heat. Only drifting a bit if I'm stopped for 2 minutes after a 70 MPH freeway run. It drops right away. My 302 car runs like you are describing. Neither puke. An infrared temp tool is the way to check for certain, unless you go with a mechanical unit.
Thanks for the help everyone. I appreciate it!