ZR-1 Block Numbers

[LGAFF]

Not sure if these are posted or not...


ZR-1 Block #s


10090511...350.....90....2...LT-5, ZR1 Vette, 375hp

10153558...350...91-92...4...LT-5, ZR1 Vette, 375hp

10199001...350...93-95...4...LT-5, ZR1 Vette, 405hp

[LGAFF]

I thought this might help in decoding Dominic's block, but I did not find this referenced on the spare block that I have.

It has 10ZSH 91100015 on the side.

I did notice on the front drivers side it is numbered with 1059...I am wondering if this is the sequence of LT-5s built...the car is # 702 so its possible.

[XfireZ51]

Lee,

Maybe Gordon Killebrew could be of help on this.
Didn't my block have the 9001 number?

[LGAFF]

Found it, the 90 actually has a 91 block stamp 10153558

Also Block and Girdle are mated with the same stamped # 1059

[1989ZR1#74]

10ZSH 91100015 ??

10ZSH: 1990 MY 375HP/350CI, Manual Transmission Electronic A/C

91100015 is short 2 digits. Are you sure that's the number?

It should start with an X for MM Stilwater
last 4 are that days sequence, but the date derivative can't be right.
So should look something like this:

X911100015:
X = MM
9 = 1989
11 = November
10 = 10th
0015 = 15th LT5 assembled that day.

Eric

[LGAFF]

I will look, does your motor have matching stamps on the block and girdle?


Date Stamp from #702

http://i134.photobucket.com/albums/q115/lgaff/DSCN0391.jpg

[1989ZR1#74]

http://www.syreal.com/702vinstamp.jpg


This LT5 came from the 702nd 1990 built. It's VIN is: 1G1YZ23J8L5800702
It is/was a Black/Black

It's block casting date was Tuesday 10/03/1989. Unlike non LT5s that have raised cast in dates the LT5 casting date is "stamped" into the block. This number will supesede the date on the "oil pan" boss.

[LGAFF]

So


10ZAA X 206170003

Is this an LT-5 produced on 6/17/1992 and the third motor produced?


This is Dominics motor.....VIN stamp area does not match the car

This is the stamp were the VIN traditionally is

http://i134.photobucket.com/albums/q115/lgaff/DSCN0444.jpg

100991 14

[Eric870]

My 1990 #740, the motor was built on 11/20/89 5th motor of the day.10ZSHX911200005

Question: My Build Sheet Date of my car is 89/321. Does that = 11/16/89? That is 4 day before my motor was built.:dontknow:

[bdw18_123]

More LT5 stamp weirdness? My '90 ZR-1 LT5 re-stampings are still a mystery also. :confused: :dontknow: :mrgreen:

Here is a recap of mine:

#2299, MM LT5 number re-stamp:

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0837.jpg


VIN cross-out & block casting date (passenger side of engine):

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0844.jpg


VIN stamp (driver side of engine):

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0847.jpg


Invoice for the car has 5/22/90 as the "PRICED" date, which I think is supposed to be the build date? And 11/22/90 is when the car was delivered to the original buyer.

[Eric870]

So


10ZAA X 206170003

Is this an LT-5 produced on 6/17/1992 and the third motor produced?


This is Dominics motor.....VIN stamp area does not match the car

This is the stamp were the VIN traditionally is

http://i134.photobucket.com/albums/q115/lgaff/DSCN0444.jpg

100991 14
Lee,

Is that a stamp on the head?

[1989ZR1#74]

My 1990 #740, the motor was built on 11/20/89 5th motor of the day.10ZSHX911200005

Question: My Build Sheet Date of my car is 89/321. Does that = 11/16/89? That is 4 day before my motor was built.:dontknow:

89/321 or the 321st day of 1989. This is an "ordinal" date. Since 1989 was a leap year this does in fact = November 16th, 1989. but....

That is not the date the car was actually built that was the date the sheet was printed. The lag varies, but at least you know the car was not built before that date. The LT5 production was going at full speed and the gap in time from MM to BG was very small. So I would suspect that #740 was built shortly after 11/20, say 11/21/1989 (my 21st birthday ironically enough!). The best way for you to find out when you car was built is to order the Vehicle Invoice from:

http://www.gmmediaarchive.com/

Its $50 and it tells you what date it was assembled and what date it shipped and where it went.

Eric

[1989ZR1#74]

Yes:

X=MM
2=1992
06=June
17=17th
0003=3rd LT5 assembled on 06/17

A very late 1992 I might add. Must be a VIN at the tail end of the MY.

I can't really see the stamp in the photo can you post a larger version? Is there a stamp on the Driver's side? Eric

So


10ZAA X 206170003

Is this an LT-5 produced on 6/17/1992 and the third motor produced?


This is Dominics motor.....VIN stamp area does not match the car

This is the stamp were the VIN traditionally is

http://i134.photobucket.com/albums/q115/lgaff/DSCN0444.jpg

100991 14

[1989ZR1#74]

So


10ZAA X 206170003

Is this an LT-5 produced on 6/17/1992 and the third motor produced?


This is Dominics motor.....VIN stamp area does not match the car

This is the stamp were the VIN traditionally is

http://i134.photobucket.com/albums/q115/lgaff/DSCN0444.jpg

100991 14

I think that the 100991 would be the casting date of the block. October 09, 1991. THis would have been the correct casting for a 1992 model year, just very early. I would suspect that the absense of a VIN may indicate that this was a service replacement, or the stamp appears lower then I would normally see. It could be that there just wasn't room for the VIN, but the 8 month lag is outside of my comfort zone making any judgements on the block.

[1989ZR1#74]

More LT5 stamp weirdness? My '90 ZR-1 LT5 re-stampings are still a mystery also. :confused: :dontknow: :mrgreen:

Here is a recap of mine:

#2299, MM LT5 number re-stamp:

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0837.jpg


VIN cross-out & block casting date (passenger side of engine):

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0844.jpg


VIN stamp (driver side of engine):

http://i13.photobucket.com/albums/a292/bdw18_123/IMG_0847.jpg


Invoice for the car has 5/22/90 as the "PRICED" date, which I think is supposed to be the build date? And 11/22/90 is when the car was delivered to the original buyer.


Priced date is the date I am comfortable with calling the build date. Now there can be a lag. What was the shipping date? Corvettes sit for 7 to 10 days in the "hold lot" before they go "accross the fence" to the ship lot. So back 7 days off the ship date.

This one is still a mystery to me. I think it was a double Gaff. 1 at MM and 1 at BG. Remember that for evry 1 ZR-1 3 L98s were built on the line. So the engine stamper may have picked up the wrong L98 Stamp and wacked the block. Then XXX'd it out and applied the correct stamp. The MM stamp is the one I don't quite get yet, but based on our previous post on this one I am leaning that way as well. Eric

[LGAFF]

So would a Mid June built motor be for a 92 or a 93 car......2 bolt or 4 bolt main?

[1989ZR1#74]

So would a Mid June built motor be for a 92 or a 93 car......2 bolt or 4 bolt main?

I forgot that bit:

10ZAA = 1992 350 ZR-1 DOHC 32V MT

[XfireZ51]

So


10ZAA X 206170003

Is this an LT-5 produced on 6/17/1992 and the third motor produced?


This is Dominics motor.....VIN stamp area does not match the car

This is the stamp were the VIN traditionally is

http://i134.photobucket.com/albums/q115/lgaff/DSCN0444.jpg

100991 14

Whe did they start building 4 bolt main motors>

[1989ZR1#74]

Whe did they start building 4 bolt main motors>

1993 - 1995 4 bolts

[LGAFF]

1993 - 1995 4 bolts

I think the question is, were the 93 motors built solely in 93 and after or was production started before......when Dominic bought the car he was told it had a service motor, but owner was not sure what year. I think the plenum indicates a 92, but were wondering if there was a possibility this could be a 4 bolt short block.

[1989ZR1#74]

I think the question is, were the 93 motors built solely in 93 and after or was production started before......when Dominic bought the car he was told it had a service motor, but owner was not sure what year. I think the plenum indicates a 92, but were wondering if there was a possibility this could be a 4 bolt short block.

ZAA is a 2 bolt 1992 engine suffix. the casting date appears to be 10/09/1991. That is long before the 1993 model year, and they built 1992 MY Corvettes until July, a couple of weeks after the block was assembled

I guess you may never know until you dig in and look at it. But I would say no if I had to guess.

[XfireZ51]

As I understood it, the assembly of LT-5 motors had pretty well ended by 91-92. That includes service motors. The date on the hood indicates the car was built in June of 92. That coincides well with the VIN# being 474.

[LGAFF]

So does the 1059# that is stamped into the block and the girdle 0f 90 ZR-1 #702 indicate production sequence?

[1989ZR1#74]

So does the 1059# that is stamped into the block and the girdle 0f 90 ZR-1 #702 indicate production sequence?
I don't think so, do you have a picture of the stamps? I have found matching numbers stamped in the heads and cam covers of 1989 #058. They are in the 600s.

[LGAFF]

http://i134.photobucket.com/albums/q115/lgaff/DSCN1063.jpg
D/sFront of block


http://i134.photobucket.com/albums/q115/lgaff/DSCN1062.jpg

D/sFront of Girdle

[LGAFF]

22 motors were produced each day
1992 Birmel went out of business
Last LT-5 was produced on 11/24/93

Hard to say if a 6/17/92 LT-5 would be a 2 or 4......we might be able to find the block # and it would tell us

[bdw18_123]

Priced date is the date I am comfortable with calling the build date. Now there can be a lag. What was the shipping date? Corvettes sit for 7 to 10 days in the "hold lot" before they go "accross the fence" to the ship lot. So back 7 days off the ship date.

This one is still a mystery to me. I think it was a double Gaff. 1 at MM and 1 at BG. Remember that for evry 1 ZR-1 3 L98s were built on the line. So the engine stamper may have picked up the wrong L98 Stamp and wacked the block. Then XXX'd it out and applied the correct stamp. The MM stamp is the one I don't quite get yet, but based on our previous post on this one I am leaning that way as well. Eric

The "SHIPPED" date is 5/24/90, only 2 days after the "PRICED" date. Couldn't have sat for 7 days, could it? "INVOICE" date is also 5/24/90.

You're probably right about the re-stamps just being a screw up. Just so happened that both plants messed up on the same car! :mrgreen: But still seems strange for there to be such a big gap between the block casting date (03/07/90) and the build/priced date (5/22/90), especially since ZR-1's were in high demand at the time. Over 2 and a half months.

On the MM stamp, they didn't completely grind out the original number, you can still make out part of the original numbers. I'm pretty sure that the last 4 digits were "2299", which would match the last 4 of the VIN. Interesting mistake for them to make, would mean they knew that this LT5 was going to be for 2299.

[-=Jeff=-]

just drop the pan already.. :-D

[A26B]

Look at the front cover to tell if it is a 4 bolt main engine. Lwr corner, driver side rounded = 375 hp 2 bolt, square = 405 4bolt.

[-=Jeff=-]

Look at the front cover to tell if it is a 4 bolt main engine. Lwr corner, driver side rounded = 375 hp 2 bolt, square = 405 4bolt.
Aw, Jerry now you are taking the fun out of it.. :sign10:

good to know though

[1989ZR1#74]

The "SHIPPED" date is 5/24/90, only 2 days after the "PRICED" date. Couldn't have sat for 7 days, could it? "INVOICE" date is also 5/24/90.

You're probably right about the re-stamps just being a screw up. Just so happened that both plants messed up on the same car! :mrgreen: But still seems strange for there to be such a big gap between the block casting date (03/07/90) and the build/priced date (5/22/90), especially since ZR-1's were in high demand at the time. Over 2 and a half months.

On the MM stamp, they didn't completely grind out the original number, you can still make out part of the original numbers. I'm pretty sure that the last 4 digits were "2299", which would match the last 4 of the VIN. Interesting mistake for them to make, would mean they knew that this LT5 was going to be for 2299.

They put them in a hold lot for 7 to 10 days incase they find something on the line during that time they can repair the ones in the Hold Lot.

The build date is really a moving target as the car isn't built instantly. You really sort of have to settle on a range. I would guess the car left the plant (meaning drove outside) 7 - 10 days prior to shipping. So probably the 5/17 time frame. The VIN number on the Boss seems almost impossible given the type of number the MM stamp is. They would only have to change the last digit maybe two on the stamp. Although if I had to guess since this is block #1 on Tuesday May 15th 1990, The stamper forgot do index the stamp forward by one day. Probably had a X0051400XX number. (although that would not show 2299 on it now would it.) Eric

[1989ZR1#74]

http://i134.photobucket.com/albums/q115/lgaff/DSCN1063.jpg
D/sFront of block


http://i134.photobucket.com/albums/q115/lgaff/DSCN1062.jpg

D/sFront of Girdle

The Girdle and the Block are two different parts.

If so are they machined together, or matched in any way?

The theory I would have are:

1: They are matched and they would need to live out their lives together so they assign some arbitrary sequence number like the heads on 1989 #058:

http://www.syreal.com/058drivestamp.jpg

http://www.syreal.com/058passstamp.JPG


My bet it was simply some kind of MM internal number assigned to a replacement block. Like the numbers on the heads.

[LGAFF]

I think we have to many topics going at once on this thread, the 1059 stamp is from the 90 #702....that one if the original motor.

[1989ZR1#74]

I think we have to many topics going at once on this thread, the 1059 stamp is from the 90 #702....that one if the original motor.

Yikes, sorry about the confusion. I am all mixed up.. OK not sure what that number is only theory #1 would apply:

"1: They are matched and they would need to live out their lives together so they assign some arbitrary sequence number like the heads on 1989 #058:"

[1989ZR1#74]

So this thread has:

#1: 1G1YZ23J8L5800702 LT5, Part#10153558, Block cast date of 10/03/1989 With 1059 stamped in Girdle and Block

Question: what does the 1059 mean?

#2: Dominic's 10ZAA X 206170003 LT5 with a cast date of 10/09/1991 This is identified as a service replacement without a VIN stamp.

Question: is it a 4 bolt?

#3: Eric870's 1G1YZ23J5L5800740, MM Stamp 10ZSH X 911200005,

Question: Build sheet date is before MM LT5 stamp date?
Answer: Since the date is when it was printed and not assembled, it is possible for the build sheet to be dated before the LT5 was assembled.

#4 bdw18_123's 1G1YZ23J6L5802299, MM Stamp 10ZSH X 005150001 Restamp.

Question: Why is both the VIN and the MM stamp "Restamped"?

[1989ZR1#74]

Ok as far as the #1059 I found this in the April 1989 issue of Corvette Fever:

http://www.syreal.com/matedblocksbsm.jpg

So they were matched, and almost all of the matched parts recieved serial "unique serial numbers" Could be why....

[A26B]

For reference, there are good pictures of just about every LT5 part on the http://www.jerrysgaskets.com website.