Noticed something interesting on my LT5...

[A26B]

I may be missing something here, but I don't see the significance of different casting dates for the upper & lower crankcases. They weren't "mated" parts until the machine work was done.

[1989ZR1#74]

Originally Posted by A26B

I may be missing something here, but I don't see the significance of different casting dates for the upper & lower crankcases. They weren't "mated" parts until the machine work was done.

Until the last post the only date I saw was 3/07/90. Now that we have a 5/08/90 it makes the gap from LT5 to ZR-1 install much shorte and typical. I am just curious why the upper took so long to get mated? any idea why?

[bdw18_123]

Originally Posted by 1989ZR1#74

Until the last post the only date I saw was 3/07/90. Now that we have a 5/08/90 it makes the gap from LT5 to ZR-1 install much shorte and typical. I am just curious why the upper took so long to get mated? any idea why?

It's actually not 5/08/90, it's 3/08/90. I guess in the picture it kind of looks like a "5", but it's actually a "3".

The oil pump also has a number printed on it (with ink) that reads: 03 0815 88. That may just be the part number, but could the first 4 numbers (03 08) refer to the date?

[1989ZR1#74]

Originally Posted by bdw18_123

It's actually not 5/08/90, it's 3/08/90. I guess in the picture it kind of looks like a "5", but it's actually a "3".

The oil pump also has a number printed on it (with ink) that reads: 03 0815 88. That may just be the part number, but could the first 4 numbers (03 08) refer to the date?

So the whole LT5 appears to be assembled around 3/7/90. 2 things I now need to know. What were the stampings for ZR-1s from March? what do other May 90 ZR-1s have for casting dates??

[1989ZR1#74]

Originally Posted by A26B

I may be missing something here, but I don't see the significance of different casting dates for the upper & lower crankcases. They weren't "mated" parts until the machine work was done.

Jerry, In you stock of LT5s are the two dates real close? Whats typical?

[bdw18_123]

Originally Posted by 1989ZR1#74

So the whole LT5 appears to be assembled around 3/7/90. 2 things I now need to know. What were the stampings for ZR-1s from March? what do other May 90 ZR-1s have for casting dates??

Originally Posted by 1989ZR1#74

Jerry, In you stock of LT5s are the two dates real close? Whats typical?

This thread seems to keep dying, so I have to bring it to life.

Discussion on this has been very interesting, still waiting on thoughts on Eric's questions above & any one with a '90 ZR-1 numbering in the 2000's (or any '90 Z really) somewhere to compare the casting date on their LT5 with their build date. 70-something day lag seems like a long time.

I want to figure this mystery out!

[phrogs]

I have my 90 LT5 from #1908 Ill check that and post photos for you.

My ZR-1 is #845 or 854 I cant recall ill have to get that one on the lift and check it.

I also have a 91 LT5 that Ill post the pics of as well so we can see what I have.

Will have to wait until later

johnny

[1989ZR1#74]

Ok let me summarize my questions that will help decipher this mystery:

For now I am focusing on the Mercury Marine oil pan stamping and casting info. Any of these questions will move the ball forward:

What is a typical casting date for a May 1990 ZR-1 LT5?

What is a typical date separation on the upper and lower castings on any 1990 LT5?

What is a typical oil pan MM stamp number for a May 1990 casting date LT5?

What is a typical oil pan MM stamp number for a March 1990 Casting date LT5?

What is a typical oil pan MM stamp number for a #2000 to #2400 1990 ZR-1?

Anyone with this information on any 1990 ZR-1 may help so don't be shy post.

[bdw18_123]

I notice BOB HDZ has 1990 ZR-1 #2293, his also would be a good one to check (in addition to phrogs' cars he said he would check and anyone else that has a '90 Z that can check) the LT5 cast date/car build date since that is the closest one to mine so far, tom tom's being the 2nd closest.

[1989ZR1#74]

I found a note in the 9/1990 Corvette Fever that supports the non warrantee exchange that we discussed early in the thread. This supports the conclusion that the LT5 in #2299 was not a repaired LT5.