Ok. I have an 88 f150 4.9. No a/c. So I get a heater core, and notic before I install it the box says"with a/c". So I take it back, and go to another store to get the "without a/c". I even check the part number with the guy. So I go to replace it and its the wrong one! Its too small and the pipes are wrong. The first one was probably the right size but those pipes were wrong too! Any ideas?

 

Take it out and have him compare til you find the right one? Most parts will have some kind of part number on them which could help find the right one by cross reference

 

There are two different heater cores one for a high output heater one for a standard output you have to figure out which one you have. Like 94 said take your old one to the store with you to match it up.

 

I bought a brass barbed hose mender fitting 5/8 so I can take it with when I return this to napa. If there is only two styles and I know the non-a.c. doesn't work then shouldn't the a.c. style work?