Need help with zz502

[DutchSS]

Hi Guys,
I can buy a new zz502. It is a anassembled version. How can I make sure it is the zz502 and not a HT502 or zz454 ?
Thanks.

[HRBS]

it should have a GM id tag on the block near where the fuel pump boss would be. All 502's will also have 8.2L stamped on the block. ZZ502's run alum cylinder heads (part #12363390) where HT's run iron heads. As far as internals go, the cam is different and without removing it and having someone calculate the lope seperation and lift you wouldnt be able to tell by just looking at it. Hope this helps.

[DutchSS]

Thanks,
I found the block P/N 10237292.
Is this what you mean with GM ID ?

[HRBS]

No. That number would be the actual block casting numer or "part number". The block casting numbers for a HT502 and ZZ502 will be the same since the same block is used for both applications. But the serial number GM assigned to that engine will determine if it started life as a HT or ZZ. Similar to a VIN # on a car. That serial number and other info is stamped on a thin plate like a credit card and attached to the block near the fuel pump boss.

[HRBS]

here is a pic of the serial tag location.
you can kind of see it.

[chr2002ca]

Also, the ZZ454 has a mount/boss for a mechanical fuel pump, the zz502 does not.

[Vegas69]

Since it's a short block you should be able to look at the pistons. The zz has higher compression. If you can find some photos of both and print out the photos I bet you can tell the difference as well.

[DutchSS]

Thanks to you guys.