Anyone who is sure their 603.96x has the original head, can you tell me the part number? I have R 603 016 14 01 stamped in the area of the head above the injection pump. Does the R mean it's a factory replacement?

What is the part number of the latest version of this head?

Thanks,
Sixto
91 300SE
87 300SDL

This thread has some of the info

http://www.peachparts.com/shopforum/showthread.php?threadid=33443


gsxr "The latest revision head is part number 603-010-96-20."

The '91 edition of the 603 Engine Manual, 01-400 page 7, Repair notes for cylinder heads, shows a revision with "new cast no. 603 016 17 01" and a "previous cast no. 603 016 15 01", sounds like your's is a revision earlier.