My 72 350 has a plastic line going to an aftermarket guage.There is no sending unit.Do I need this unit?

 

He would have unscrewed the sending unit from the block to install the aftermarket tube. It's up to you if you want to change it back over from the aftermarket guage back to the original. If the unit is still on the car it should still be in the wiring harness. personally I like having the guage rather than an idiot light but either way is ok.

 

Why not put a "t" fitting in and run both?

 

If you decide to reuse the aftermarket gauge with the plastic tubing...do yourself a big favor,buy some insurance,ditch the plastic and upgrade to copper tubing.

 

dido...i had the plastic tube fail under the dash and on the carpet, made a mess.....I replaced it with copper....

 

Thanks. I'll go one up and use stainless