The correct bushings can be bought from the parts suppliers.

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Jeff All you have to do to put the pre 57 temp sender in your head is change the bushing that is pressed into the head to the one that is used in the early y blocks then just screw the sender in Carl

I have a 62 292 that will be going in my 55 and noticed it has a smaller temp sending unit then the 55,I doubt I will use the 62 heads but for my gauge to work right I need to use the original sending unit so can the head be drilled out or will I have to use 55 or 56 heads since I think the smaller sending unit started in 57.

Butchering up everything I can get my hands on in Dayton Ohio