DeadStang

The casting number is: 3970010
The stamping is: V0608CTB

When I try to search these, I get a bunch of different possibilities. But the combo search doesn't come up w/anything much definitive. Ideas?

63mako

Find the casting date on the bellhousing flange. That will narrow down the year then the CTB will determine the application for that year.

DeadStang

The number I found there was the 3xxxxx number...is there another place I should look (passenger side maybe)?

63mako

Drivers side rear near the casting number. Example: C270 is a March 27 1970 casting. 3970010 was used 1968 327 and 1969-1979 350 only.
http://www.nastyz28.com/sbchevy/sblo...a_close_button
3970010 (1969-1979 350) combined with CTB can only be a 1970 High performance 350 LT1 W/4speed. NICE!!!
http://www.nastyz28.com/gm-chevy-cod...s-suffix-3.php

Easy Mike

CTB is not a Corvette engine code, but it could have been an LT-1. You will need the block casting date.

DeadStang

I looked again for a casting date code near the 3xxxxxx number, but can't find anything else visible there. Does anyone have a picture of where exactly I might look when the engine is in the car? I tried a search but couldn't come up w/anything.

Mike7143

Driver's side with block part number and pattern number:


Near top, driver's side still: I think that's the plant and shift clock and I'm not sure what the 3 is between the cast "screw heads"


And then here's on the passenger's side, the block cast date between the cast "screw heads" B252 which I believe is February 25th, 1972 for my March 13th 1972 coupe:


Someone please correct me if I'm wrong. So... 3970010 block from pattern 32 cast around 3pm during the 10am shift at the Tonawanda plant in Buffalo, NY on February 25th, 1972. I can't explain the cast 3 between screws near the shift clock casting.

BKarol

In an article I read there were 21 conveyors. In the 2nd pic the 3 would signify it went down conveyor #3.

In the last pic because of one flat head and one round head it was made on the 2nd shift.

Mike7143

Interesting note on the conveyors, never knew that. Regarding shift, does that mean 2nd shift started at 10am?

Also, I realized I have no idea what the T G N symbol is, I thought it was which plant it was cast at, but if it was Tonawanda I'd think it'd be pointing to the T? I know up front is the stamp position for engine assembly plant, but I assume that's the plant where the engine is finished (in my case V for Flint, MI) and then mates to chassis, i.e., assembly so St. Louis (12Sxxxxxx) for a 72. But the block would have been cast in Tonawanda I'd think?

Mike Ward

With very very few exceptions, all Corvette SBCs were cast and assembled at Flint. The casting date on this block has a single digit for the year which identifies it as a Flint block. Tonawanda used two digits for the year.

Mike7143

Ahh. So the block was cast AND built in Flint, then shipped to St. Louis for install. So any ideas what the TGN pointer casting is?

Don't mean to hijack DeadStang, just thought I'd post pictures that may help you locate your casting date as well as help in identifying more details on your block as well as mine!

Easy Mike

I've read the 3 indicates the mold used to cast the block.

Mike7143

I thought that was what the 32 was near the block number...

qtlow

The way alan71 once explain it was the TGN pointer designated which shift at the foundry cast the part. For example - daylight, twilight or night shift.

THREAD

Mike Ward

No, but I'd like to start a new myth.

For many years the 010 and 020 numbers found under the timing cover on some blocks were mistakenly though to mean a high percentage of nickel and tin, making the block somehow 'better'. We now know that these numbers were the last three digits of the block casting number that the mold was used for 3970010 and 3970020 but the legend lives on.

I propose a new story that the TGN stands for Tin, Gold and Nickel. If anyone finds a block with the pointer at the G, it's made of pure gold and worth a million-squillion dollars.

BKarol

Read Frank's explanation in Post #4:

http://forums.corvetteforum.com/c3-g...an-thanks.html

Alan 71

Hi,
I agree about the D, T, and N indication, but I believe the pointer with the arrow and circle of dots wasn't indicating the time of day, (not 10 a.m.), but rather the hour count with-in the shift.
Regards,
Alan

BKarol

So would that be the 7th hour?

Mike7143

Okay so the 32 is the pattern serial number, and a 3970010 block with pattern serial number 31? would have been cast at the same time with my 32 (Frank mentions pouring 2 at a time) from a mold number I don't know. As Frank put it, series XX patterns 31 and 32? Or perhaps it was incremental so pattern serial numbers 32 and 33 were in series XX. Not sure where Frank got the series (mold number) from.

As far as the clock goes, I just got that from nastyz28, but now that I re-read it that makes more sense. So it looks like my block was cast during the twilight or 2nd shift, 7 hours into the 10 hour shift. So if one knew when 2nd shift started, you could get the hour of day it was cast as well. No wonder searching Google for TGN was useless, it's apparently a D

qtlow's link was helpful, wish I had found that earlier!

Mike7143

Or if this is the case, and it's not the conveyor number, then it'd be pattern serial number 32 from mold/series 3?