I am putting a used set of pistons back in my truck. What is the cutoff date on when they changed the pistons. 2004 or 2004.5 trucks? Or 2005 trucks?
I think there is a bowl pattern difference but I cant look at the pistons as of right this minute. They have low mileage - going to get them but need to know b/c they are still in an engine that manufacture date is January of 2004.

 

2004.5 is when the change was made.

Your Jan 04 mfg date will be the older style.

 

This is an 03-04

04.5-07

 

Terry, Im pretty sure 1-1-04 and after IS the 04.5. The 03-early 04s ended in late 03.

..

 

Yikes, this is what I thought.

But I cant compare yet by just looking at them physically.

 

The pistons you melted are from an 03-04 engine. Sometime is May of 04.5 is when the engines got onto the streets with the 3 injection events and the newer piston design.

The 235, 250 and 305 HP engines have the older style like you melted.

The 325 HP engines use the newer style

 

yeah mine was made in jan 04 and is the 325 and they are the same as the second pic