check further on the gas gauge, make sure you have a good ground to the sender base and that the wire to the gauge has continuity .... for the speedo, that's not uncommon, the cable is good and driving the odo, but the speedo wheels need some help - and oil should be used very sparingly in the speedo, will eventually gum things up

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics