69 DZ Blocks

[HOT3O2]

Could someone tell me why Chevy used 4 different blocks for the 69 DZ 302 through out it's production. Was there any changes on the blocks besides the casting numbers?  Thanks

[68Zproject]

I don't know specifically what the differences were.  If you have a Colvin's By the Numbers, he lists what some of the changes were.  Most were very minor.  Also, the casting numbers could be used for other engine sizes as well.  All Chevy did was change the crank and rods to make 302's, 327's and 350's.

[william]

Sucessful manufacturing has always required continuous improvement. Starting in '67 most cars carried a 5 year 50,000 mile power train warranty. Field failures were analyzed and appropriate changes made. That's why casting numbers sometimes changed. Improvements such as 4-bolt main cylinder blocks and screw-in rocker arm studs were part of the process.

Some of the back-door factory hot-rods such as Hemis did not have the traditional warranty for obvious reasons. Chevy fully covered all of their cars and I'm sure they regretted it.

[HOT3O2]

I see there were 3 regularly used blocks in 69: 3932386, 3956618, 3970010. Where did the 3932388 block come into play? Was this a left over block Chevy was trying to get rid of ? How rare is it to see one of these (388) blocks in a 69 Z28?

[tmodel66]

According to CRG: "The 3932388 block is sometimes noted as being 'rare', but it actually was commonly used in mid-69 production."

[sam]

Again, DZ is not a block just a suffix code.

[1968RSZ28]

How rare is it to see one of these (388) blocks in a 69 Z28?

See Kurt's reply (#5) in this thread...  http://www.camaros.org/forum/index.php?topic=3267.0

Paul

[HOT3O2]

Thanks for pointing me in the right direction Paul,  That cleared things up for me.

[HOT3O2]

In reading Jerry's New book (4th Edition) he states his research shows the 388 block was used mid year between Feb. 69 thru May 69. and only in 302's. And a range of 3 to 6 weeks from casting to assembly. Has any one seen a 388 block use on any early (68) built DZ motors?

[crobjones2]

In reading Jerry's New book (4th Edition) he states his research shows the 388 block was used mid year between Feb. 69 thru May 69. and only in 302's.

Interesting, I have a 388 block May 69 cast but in a 350

[HOT3O2]

That is interesting Chris. Jerry's book did mention that some of the early 350's used the 388 block. What is the cast and assembly dates on your block?

[JKZ27]

My late November (68) built L48 is a 388 block. I also have a L48 block from a 69 full size wagon that is a 388 2 bolt main.

John

[crobjones2]

That is interesting Chris. Jerry's book did mention that some of the early 350's used the 388 block. What is the cast and assembly dates on your block?

E20 with a build of 0526

[HOT3O2]

Thanks for the reply's Chris and John. I have a 12B RS Z28 with a 388 block. Casting date(K308) and a build date(V1203DZ). I thought it was a little early to have that block in a Z but who know how they put thing together back then. Grab a block, build it, and not check numbers? I guess anything was possible.

[sam]

 They probably grabbed any 4 bolt block available for the build. Probably not to concerned about a 388,386, 010 or whatever in those days. Get the car built and sold.

[HOT3O2]

Yes your probably right Sam. The quality control back in those days is not what it is today.

[crobjones2]

My late November (68) built L48 is a 388 block. I also have a L48 block from a 69 full size wagon that is a 388 2 bolt main.

John

John
Are both your L48's from theTonawanda plant?

[Boston14]

My 11D (68) L48 is a 388 block also. It is a Tonawanda cast and built engine. T1120HB

boston14

[JKZ27]

Chris,
I know the one in my 12B SS is, I'm 99% sure the other one is too but I'll check tomorrow.

John

[JKZ27]

Yes, the other block is a Tonawanda. Strange though, looks like the cast date is I 26 8 and the assembly is T0212HN.

John

[crobjones2]

it appears that only the Flint assembled motors using this block  were 302s while the Tonawanda built motors are of the 350
I am curious if your blocks are 2 or 4 bolt? Mine is a 4 bolt

Kurt/Ed/John - does the above statement follow what is in the database?

[KurtS]

Chris,
Good observation, supported by the db. Also realize that Flint sometimes didn't make many of certain suffix codes, so that distorts it some.

[Boston14]

My 388 Tonawanda block is 4 bolt also. Tonawanda did not have the machines needed to produce 2.02"  intake valved heads, so they did not produce any 302 engines (at least that I have ever heard of). John Z or Kurt correct me if I am misinformed.

boston14

[jdv69z]

So was the 388 block cast at Tonawanda? And shipped to Flint? Or cast at both plants?

Jimmy V.

[tmodel66]

My 388 Tonawanda block is 4 bolt also. Tonawanda did not have the machines needed to produce 2.02"  intake valved heads, so they did not produce any 302 engines (at least that I have ever heard of). John Z or Kurt correct me if I am misinformed.

boston14

Could you explain this.  All it takes is a different fly cutter to put in seats. The guides were the same size. The castings were basically the same in configuration.

[Steve Shauger]

My 388 Tonawanda block is 4 bolt also. Tonawanda did not have the machines needed to produce 2.02"  intake valved heads, so they did not produce any 302 engines (at least that I have ever heard of). John Z or Kurt correct me if I am misinformed.

boston14

This issue was discussed several years ago. I recall a few orig 302's built with the 388 block.

[KurtS]

Could you explain this.  All it takes is a different fly cutter to put in seats. The guides were the same size. The castings were basically the same in configuration.

The chamber had to be clearanced for the flow. Tonawanda didn't have that tooling/station.

[JohnZ]

<<Could you explain this.  All it takes is a different fly cutter to put in seats. The guides were the same size. The castings were basically the same in configuration.>>

Photo below is a 461 chamber with 2.02/1.6 valves, but it's similar to the 462/291/186 chamber; note the added machining cut to unshroud the side of the chamber wall adjacent to the intake valve to optimize flow. Tonawanda only built small-block heads with 1.94/1.5 valves and no unshrouding cut, and didn't build any solid-lifter small-blocks; all solid-lifter small-blocks (and hydraulic-lifter L-79's) used 2.02/1.6-valves, and they were built only at Flint V-8. Flint had the transfer line station for the larger valves and the unshrouding cut, and Tonawanda didn't.

[tmodel66]

Thanks Kurt and John. Forgot about the chamber cut. I was thinking in terms of machine shop work and not assembly line work which is apples and oranges. Every step has it's own tooling.

[L78 steve]

There was also machining under the valve so not to neck down the flow on the 202's

[crobjones2]

Therefore - there are NO 302 DZ motors built at Tonawanda using the 388 block. Tonawanda, from what can be garnered from the evidence, only made 350's using the 388 block?

[Steve Shauger]

Below is a 388 (tonawanda) block assembled at flint V0318 DZ. Notice the plug is missing above the timing cover. This was in an unrestored survivor car. The interesting point is that it was assembled in flint(see stamping), and these block presumably were only cast at Tonawanda. It made no sense when it was discussed several years ago. I believe there are a couple of other examples as well. The picture attached was resized so its low resolution, but I have higher resolutions stored on another computer. The stampings look genuine.  

[HOT3O2]

Thanks for the pictures Steve, It seems to me that maybe they were short on blocks at times and had to have some of the 388's shipped in from Tonawanda.

[Steve Shauger]

Thanks for the pictures Steve, It seems to me that maybe they were short on blocks at times and had to have some of the 388's shipped in from Tonawanda.

Thats the only scenario I could come up with as well.

[Steve Shauger]

Just an FYI, the other survivor Z with a 388 block was assembled V0425DZ

[HOT3O2]

Steve, Have you ever seen or heard of any 68 built 69 Z28's with the 388 blocks?

[GaryL]

Seems like I remember several people being shot down for "original" DZ engines using Tonawanda blocks. Maybe not here, but over at TC.

[Steve Shauger]

Seems like I remember several people being shot down for "original" DZ engines using Tonawanda blocks. Maybe not here, but over at TC.

As noted it very uncommon, and it has been debated, however when you have several survivor cars with the 388 block you need to acknowledge those examples. I remember when conventional wisdom was that the 323 block was first used in 68 only, and I had a survivor 67 L78 built with one (this was 1995), then several other late built cars with the 323. Now that block is recognized as used in late 67 built cars. Things are discovered almost daily and once you have several data points with common findings you at least have to acknowledge "new information".

[HOT3O2]

I'd be curious to know what the DB has for the earliest DZ 388 block.

[JohnZ]

Seems like I remember several people being shot down for "original" DZ engines using Tonawanda blocks. Maybe not here, but over at TC.

As I recall, the key issue wasn't a Tonawanda-cast block, it was a "T"-prefixed "DZ" stamp on the pad; a Tonawanda-cast block is (remotely) possible, but a "T" stamp on the pad is not.

[sixt9x33rs]

As I have mentioned several years ago, on Team Camaro, I have a 69 RS Z which is an unmolested 35K mile car and for some reason on the POP There is a "T" instead of a "V" in the motor assembly location on the plate. My block is a Flint cast block as well. The stamp on the block corresponds withe the POP as well. My engine is a second week assembly; tranny, rear end, interior, carpet, shifter, body panels, glass except w/s all born with. Can't make out a vin in the rough cast area. Car had 90% original paint when purchased since has been repainted. When purchased looked like a old car that had been sitting in a building with years of dust and grime on it, surface rust underneath and on the motor.

Couple guys on this site know the car.

Restamped  mis stamped, I don't know or really care...it is a cool old time capsule.

Lawrence

[HOT3O2]

Hey Lawrence, Would love to see some pic's of your car. You don't come across too many in that condition.

[sixt9x33rs]

Hey Lawrence, Would love to see some pic's of your car. You don't come across too many in that condition.

It's painted now and the underside painted too. PM me and I can send pics before paint.

[HOT3O2]

If the 388 block was cast at Tonawanda, Were the other 3 DZ blocks cast at Flint?

[JohnZ]

If the 388 block was cast at Tonawanda, Were the other 3 DZ blocks cast at Flint?

Yes. All of them were also cast at Flint (actually at Saginaw).