Author Topic: DZ 302 186 heads  (Read 12248 times)

Lukes 69 z28

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DZ 302 186 heads
« on: April 07, 2008, 04:53:20 AM »
My 69 Z28 has the original engine dated I-8-9,010 block stamped VO908DZ .The original heads are missing. Does anyone have this same dated block and stamp so I could get the correct head dates? Build date of car is Norwood 09C  1969. thanks

firstgenaddict

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Re: DZ 302 186 heads
« Reply #1 on: April 07, 2008, 08:15:29 PM »
A few weeks before the assembly date maybe a month being that it is an early car. 
James
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Dusk Blue Z

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Re: DZ 302 186 heads
« Reply #2 on: April 07, 2008, 09:07:26 PM »
Wouldn't a I-8-9 block make it a late car? A couple of weeks or so before should be OK.

Mike

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Re: DZ 302 186 heads
« Reply #3 on: April 07, 2008, 11:17:06 PM »
duh.... I knew that when I read it and got distracted at work... then wrote the response...
James
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melav8r

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Re: DZ 302 186 heads
« Reply #4 on: April 08, 2008, 02:02:30 AM »
I would say H 30 9's give or take a few days, typically 10-14 days before the engine assembly date is ideal, nothing set in stone on that one, just don't go any earlier than a month and not later than about 5 days prior to the engine assembly date. : )

JohnZ

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Re: DZ 302 186 heads
« Reply #5 on: April 08, 2008, 02:54:50 PM »
just don't go any earlier than a month and not later than about 5 days prior to the engine assembly date. : )

Actually, it can be closer than five days between casting and machining/assembly; his block was cast on September 8th, and assembled the same day. Although it's not the "norm", we've documented a number of Corvette small-blocks from Flint that were cast and machined/assembled on the same day (cast early on the first shift at Saginaw, assembled late on the second shift at Flint). More "normative" separation, however, invites less scrutiny.
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melav8r

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Re: DZ 302 186 heads
« Reply #6 on: April 08, 2008, 09:01:38 PM »
just don't go any earlier than a month and not later than about 5 days prior to the engine assembly date. : )

Actually, it can be closer than five days between casting and machining/assembly; his block was cast on September 8th, and assembled the same day. Although it's not the "norm", we've documented a number of Corvette small-blocks from Flint that were cast and machined/assembled on the same day (cast early on the first shift at Saginaw, assembled late on the second shift at Flint). More "normative" separation, however, invites less scrutiny.

John,
Are you saying you have documented heads cast the same day as the engine assembly?.

Lukes 69 z28

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Re: DZ 302 186 heads
« Reply #7 on: April 09, 2008, 03:40:41 AM »
A while back a person told me he had the same build date and had H-29-9 heads .I just wanted a second opinion on another Z dated and  stamped the same as mine.

KurtS

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Re: DZ 302 186 heads
« Reply #8 on: April 15, 2008, 03:35:34 AM »
Are you saying you have documented heads cast the same day as the engine assembly?.
I don't recall if I've seen the same day, but the day before for sure. Intake (cast iron) can be the same way.
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crobjones2

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Re: DZ 302 186 heads
« Reply #9 on: April 15, 2008, 05:55:19 AM »
Quote
Actually, it can be closer than five days between casting and machining/assembly

John
What was an average time from casting to assembly?
Did Chevrolet run the engine shop 7 days a week?

I ask because I thought my head - assembly time was short - cast on a thursday and assembled on a monday

Thanks for any insight you can provide
Chris
Chris
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JohnZ

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Re: DZ 302 186 heads
« Reply #10 on: April 15, 2008, 02:03:37 PM »
Quote
Actually, it can be closer than five days between casting and machining/assembly

John
What was an average time from casting to assembly?
Did Chevrolet run the engine shop 7 days a week?

I ask because I thought my head - assembly time was short - cast on a thursday and assembled on a monday

Thanks for any insight you can provide
Chris

Foundries never shut down - the melt cupolas ran continuously, although pouring of castings was normally a six-day operation on two 10-hour shifts; the Saginaw and Tonawanda foundries each produced about 55,000 castings per day for their respective engine plants. The Flint and Tonawanda engine plants ran the machining departments on three shifts, and assembly on two shifts, producing about 5500 engines per day each (one every 12 seconds).

Castings "typically" were machined within 2-10 days, although it could be much longer depending on inventory and demand for specific castings; production scheduling and inventory control in the 60's was nowhere near as precise as it is today.
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Lukes 69 z28

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Re: DZ 302 186 heads
« Reply #11 on: April 17, 2008, 02:42:16 AM »
Thanks for the help everyone,but I would still like to talk to someone who has a car that is dated close to mine.

KurtS

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Re: DZ 302 186 heads
« Reply #12 on: April 19, 2008, 04:41:15 AM »
A while back a person told me he had the same build date and had H-29-9 heads .I just wanted a second opinion on another Z dated and  stamped the same as mine.
Sometimes you gotta be happy you got a first opinion. :) That's kinda looking for a needle in a haystack.

They should be close.
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melav8r

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Re: DZ 302 186 heads
« Reply #13 on: May 16, 2008, 05:38:58 PM »
Foundries never shut down - the melt cupolas ran continuously, although pouring of castings was normally a six-day operation on two 10-hour shifts; the Saginaw and Tonawanda foundries each produced about 55,000 castings per day for their respective engine plants. The Flint and Tonawanda engine plants ran the machining departments on three shifts, and assembly on two shifts, producing about 5500 engines per day each (one every 12 seconds).

Castings "typically" were machined within 2-10 days, although it could be much longer depending on inventory and demand for specific castings; production scheduling and inventory control in the 60's was nowhere near as precise as it is today.

Is there a way to identify which foundry a block was cast, ie: Tonawanda vs Flint?

JohnZ

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Re: DZ 302 186 heads
« Reply #14 on: May 16, 2008, 10:54:43 PM »
Is there a way to identify which foundry a block was cast, ie: Tonawanda vs Flint?

Definitely. The year portion of the casting date code on a Tonawanda block is two digits, and it's only one digit on a Saginaw casting (like C 3 9 on a Saginaw block, which would be C 3 69 on a Tonawanda block. Also, Saginaw/Flint blocks had a 1/8" NPT square-head plug in the front of the block, just above about 11 o'clock on the timing cover; Tonawanda blocks didn't have the hole or the plug. Photo below.

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Flowjoe

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Re: DZ 302 186 heads
« Reply #15 on: May 17, 2008, 03:37:01 AM »


... Also, Saginaw/Flint blocks had a 1/8" NPT square-head plug in the front of the block, just above about 11 o'clock on the timing cover; Tonawanda blocks didn't have the hole or the plug. Photo below.



any reason why?  Wouldn't corporate GM use one mold design across all corporate entities for standardization?

melav8r

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Re: DZ 302 186 heads
« Reply #16 on: May 17, 2008, 05:31:57 AM »
Definitely. The year portion of the casting date code on a Tonawanda block is two digits, and it's only one digit on a Saginaw casting (like C 3 9 on a Saginaw block, which would be C 3 69 on a Tonawanda block. Also, Saginaw/Flint blocks had a 1/8" NPT square-head plug in the front of the block, just above about 11 o'clock on the timing cover; Tonawanda blocks didn't have the hole or the plug...
Does that apply to Small Blocks, specifically trying to identify any differences between a Tonawanda cast small block and a Flint Casting.
« Last Edit: May 17, 2008, 05:38:45 AM by melav8r »

JohnZ

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Re: DZ 302 186 heads
« Reply #17 on: May 17, 2008, 05:56:09 PM »
any reason why?  Wouldn't corporate GM use one mold design across all corporate entities for standardization?

The block machining process differed slightly between Flint and Tonawanda; although both sets of tooling were installed in 1954, Flint modified theirs for what they considered to be a more reliable method of creating an intersection in the front oil gallery by gun-drilling that hole from the outside and then plugging it. Tonawanda elected to stay with the base design and create the intersection from the inside; this difference remained all the way through the production run of the Gen I block.

If you find a block with a single digit for the year in the casting date and the plug in the front, it's a Flint block; if the year is two digits and there's no plug, it's a Tonawanda block.
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melav8r

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Re: DZ 302 186 heads
« Reply #18 on: May 17, 2008, 07:28:17 PM »
JohnZ, What about a '68-'69 SBC with a single digit for the year, possibly no front plug, but stamped with a Tonawanda assembly-date/engine-i.d. stamp? Until I confirm the front plug, is there a possibility Flint blocks were shipped to and assembled in Tonawanda?

KurtS

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Re: DZ 302 186 heads
« Reply #19 on: May 18, 2008, 04:02:23 AM »
Both plants had dedicated foundries nearby, so generally no blocks were exchanged between them. But exceptions could occur.

Post or email me a pic of the pad and I'll take a look.
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Flowjoe

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Re: DZ 302 186 heads
« Reply #20 on: May 19, 2008, 12:23:10 AM »
any reason why?  Wouldn't corporate GM use one mold design across all corporate entities for standardization?

The block machining process differed slightly between Flint and Tonawanda; although both sets of tooling were installed in 1954, Flint modified theirs for what they considered to be a more reliable method of creating an intersection in the front oil gallery by gun-drilling that hole from the outside and then plugging it. Tonawanda elected to stay with the base design and create the intersection from the inside; this difference remained all the way through the production run of the Gen I block.

If you find a block with a single digit for the year in the casting date and the plug in the front, it's a Flint block; if the year is two digits and there's no plug, it's a Tonawanda block.
that's very interesting to know - thanks John.  It does still stun me that corporate would allow that much discretion on such a key component and not adopt (or require) one or the other as "best practice".

KurtS

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Re: DZ 302 186 heads
« Reply #21 on: May 19, 2008, 05:58:56 PM »
Best practice?? Back then, the plants and the divisions were all competitive. There was no company-wide vision. They didn't see the freight train coming.....
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melav8r

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Re: DZ 302 186 heads
« Reply #22 on: May 19, 2008, 07:36:32 PM »
Both plants had dedicated foundries nearby, so generally no blocks were exchanged between them. But exceptions could occur.

Post or email me a pic of the pad and I'll take a look.

Heres the link, seller just informed me no front plug so with the stamp and JohnZ's info it's definitely a Tonawanda block, but it has a single digit for the year.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=190222656104&ssPageName=ADME:X:RTQ:MOTORS:1123

crobjones2

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Re: DZ 302 186 heads
« Reply #23 on: May 19, 2008, 09:24:26 PM »
I have to concur with melav8r - my 350  2388 block is dated E209 - there is no plug
It is only a single year digit- could this be a difference for Tonawanda between 68 and 69?
Chris
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KurtS

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Re: DZ 302 186 heads
« Reply #24 on: May 20, 2008, 02:51:17 AM »
I think John may be incorrect on that detail. (gasp!) I don't recall ever seeing a 67-69 block with two digits for the year in the cast date.
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JohnZ

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Re: DZ 302 186 heads
« Reply #25 on: May 20, 2008, 02:28:10 PM »
I'm not positive about the 2-digit year code after '67 (my Corvette focus is '57-'67, and the 2-digit year code was the Tonawanda small-block discriminator during those years); Tonawanda big-block casting date codes used a single digit for the year. They may have changed the small-block date code format during and after 1967.
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melav8r

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Re: DZ 302 186 heads
« Reply #26 on: May 22, 2008, 01:30:34 AM »
I'm not positive about the 2-digit year code after '67 (my Corvette focus is '57-'67, and the 2-digit year code was the Tonawanda small-block discriminator during those years); Tonawanda big-block casting date codes used a single digit for the year. They may have changed the small-block date code format during and after 1967.

Thanks for the info JohnZ, apparently the "T" blocks also use a single digit year code for model year '69, whether cast in 68 or 69, but I concur on the missing front plug. here's a T on the face of another "T" block in the area behind the timing chain. I wonder if that identifies it as a Tonawanda casting?

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260242701219&ssPageName=ADME:X:AAQ:MOTORS:1123

JohnZ

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Re: DZ 302 186 heads
« Reply #27 on: May 22, 2008, 02:47:17 PM »
here's a T on the face of another "T" block in the area behind the timing chain. I wonder if that identifies it as a Tonawanda casting?

Several of the other pattern identifiers have a "T" as well, so it's probably a Tonawanda casting - can't tell from the photos if it has the front plug or not.
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jmcbeth

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Re: DZ 302 186 heads
« Reply #28 on: July 03, 2008, 07:50:54 PM »
Thanks for the help everyone,but I would still like to talk to someone who has a car that is dated close to mine.

Luke,

If you still need someone with a date close yours, please reply. Mine is 09C. Last digits of Vin are 685955.
John
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69Z28-RS

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Re: DZ 302 186 heads
« Reply #29 on: November 04, 2008, 08:15:13 PM »
I'm a little late on this thread, but my original unrestored Z28/RS is also an '09C' build week.  I'd love to see some comparatiive information for similar cars.   I'm also in the need of a set of correctly dated '186 heads', as when I bought my car, one head was damaged (a stud had pulled out and been welded back! ).   when I rebuilt the engine in 1977, I sold those heads and bought an almost new set of 'angle plug' heads - which were very hot at the time - for less money then rebuilding the ones I had!  (good deal then, bad for restoration!).  *G*  My engine date is also late August..  so I've been looking for mid-August 1969 dated heads.   I've several sets of '186 heads for ealrier in '69, and also from '70 yr for trade if anyone has date-compatible ones to trade.  Luke and John:  I'd love to compare data with you.  I'm attempting my first image attachment herein, but I don't know if it is going to work.

PS.  Re the relationship of casting to assembly dates:   My '69 302 in my camaro was cast one day prior to assembly.   I've got an original '57 Bel Air (283) which was cast/assembled on the same day (which I've always thought was amazing!).. 
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
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69Z28-RS

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Re: DZ 302 186 heads
« Reply #30 on: November 04, 2008, 08:21:36 PM »
OK.  :)   that image worked, so I'll try another with my door mounted mfg sticker... with the VIN.  My car has original paint from the cowl back (only front clip has been repainted, probably from a minor accident in it's early years;   I was amazed even in 1976 when I bought the car that the mfg sticker was still on the door!  since it's been sitting in my basement garage since 1980, the sticker is still there!   :)
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

samanatoo

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Re: DZ 302 186 heads
« Reply #31 on: November 05, 2008, 12:51:59 PM »
Is your car orange on orange houndstooth??  Mine is do not see them too often.

samanatoo

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Re: DZ 302 186 heads
« Reply #32 on: November 05, 2008, 12:53:55 PM »
My block is cast on May26th/ Heads cast on May 27th/ engine build May30th

69Z28-RS

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Re: DZ 302 186 heads
« Reply #33 on: November 05, 2008, 08:06:52 PM »
Is your car orange on orange houndstooth??  Mine is do not see them too often.

Yes, it is.  It's a 720 trim, 72 B code car, 09C build with 08/27 assembled engine.  all the mechanicals are original.  I'm trying to find the alternator that I removed in 1982 or so.. it's in my garage somewhere along with the original coil - I put on a Judson electronic mag in 1976!!  :)  

I thought the interior was ugly when I first saw it in 1976, but traded for it because it was different and unusual (traded a very strong running and original '68 blue Z28 for it).  I guess the color combo *grows on you* because now I like it, and everyone that has seen it wants to buy it...  *S*   

Here's a photo of my original interior (wear on the driver's seat, but otherwise good).   I plan to do some repair on the driver's seat, and maintain itin as 'factory original' condition as I can.
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan