I know that these are not casting numbers they are serial numbers from original manufacturing in 1993! They are 374's as you can see in my intitial post in the new members area!
I would show you more pics but I don't want you all to get mad at me for clogging up the forum!

 

you can keep it in one thread and not clog up the forum. don't be a smart ***

i've never heard of the 040 casting number craby...can you find out what those were off of please?

 

the heads are all the same if the casting numbers are the same. the 10207643 is a prefered lt1 head. it came out a little latter and it has a little more material to work with. lloyd prefers this head to work with. did not want to work with any other to do my le2 job. had me check the number before we started. so the manufacure number on the heads will tell u nothing. like i said if the head has had any aditional work there would be more markings. so u know what to look for this is from a picture i took before the heads got done, kinda rusty.

 

i think they are 95 and newer but not sure. they are a stonger head according to le

 

i'm thinking that's 643...i know my 97 is 561 and they are weaker. generally the 374 and 643 are the heads for porting...i could be wrong i guess

 

yep its a 643. sorry bout that. had to go out and look on the motor. lol. picture sucks.

 

have u tried to google those numbers? with a marker note on the inside i wonder if they have been reconditioned. my heads have some numbers like that on the ends and lloyd was not interested in those numbers so i dont think they have anything of interest associated with them. havnt found anything anyways.

 

No. The heads have never been touched. I took a picture when I removed the valve cover. The 16 and 18 are from GM's installation. I have seen numbers like that on another 93 head on Shoe Boxes site. His says 36 or something on one that I noticed. The other numbers stamped on the front of the heads are also original from GM. They are serial numbers not part numbers.
Thanks

 

Here's some pics of the head's original serial number from GM, so in the future you may be able to identify an original 93 Z-28 engine.[IMG][/IMG]

 

And the other.