My 69 Bee has a low fuel gauge temp and oil. I know the oil one is off by about 20psi and the temp always reads low and I've put two diffrent fuel senders in and they dont read quite right either. Could it be the voltage limiter on the rear of the gauge cluster?

it sure can. so could a bad ground on each sending unit or corrosion on the bul;khead terminals. the gauges ground through the sending units. Check for a good ground between the body of the sending unit (where it screws into the intake or the plate of the sending unit) to battery ground. if you have more than a few ohns (like more than 10 ohms) thats a problem

You really should swap out the voltage limiter with a solid state one. they are more accurate and reliable

i had that problem too, plus the gauges read even lower when i turned on my headlights. Napa has the dash limiter, if i remember correctly it was about $8, i bought a few of them, but changing that out totally solved the gauges reading low....