I recently purchased an 05 Tahoe 4.8ltr and I'm changing plugs and wires and coil packs! I glanced under the hood and saw they were round and ordered round ones. Now upon further inspection it appears that they had round ones but should have been square. What happens if you have the wrong coil packs in?

 

you will get square sparks

 

Really not funny! Thanks for your help.

 

Can you take them back, and exchange? The only thing I would add is they probably are ok, if they will physically install.

 

Mysteriously, as if by magic, your Tahoe will also run on those coils.

The only major difference between the round and square coils is who made them- Delphi made the round ones and Melco made the square ones. I can’t recall exactly which years, but depending on that, the mounting brackets were slightly different and I think the plug wires were different lengths. Otherwise the wiring and operation was the same.

Some people will swear that installing the round coils with heat sinks improved performance, but as with many things, that seems to be a relative claim.