cylinder head casting number locations

I am rebuilding the motor on my 2003 dodge ram 5.7 hemi.
I was going to order a set of heads on ebay and they are asking for casting numbers off my old heads. Where will I find the casting numbers on my heads?

Welcome here John. I do not know Hemis but someone here will. EDIT you might Google it & see if there are any posts on that on a Hemi site and or call any of the MFR's that sell aftermarket Hemi heads or even call Ma herself & see if any of the MP techs know.

The guys that hang at the Moparts Gen III Hemi Forum will know.
Ask over there.

https://board.moparts.org/ubbthreads/ubbthreads.php/forums/32/1/gen-iii-hemi-tech.html