427 Aluminum Block Numbers

**69LM1** · #1 02-19-2004, 02:37 AM

I am looking at buying this block, what can you guys tell from these numbers? Vette or CoPo, or either? Any help is appreciated!!!

-The casting numbers at the rear of the block are "3916321"(it has 4 bolt mains).

-The casting date is hard to make out but looks like "1 27 7".

-The stamped numbers on the front deck looks like "TI0I6TH"

-There is a partial vin on the block that reads " 18J282724"

-The crank is forged, cross-drilled and ".010/.010.

-The rods are 7/16 full floated dimple rods.

Rich

jg95z28 · #2 02-19-2004, 03:22 AM

3916321 = 427 cid-425hp Passenger or 400hp, 430, 435 Vette (4-bolt)
I 27 7 = Sep. 27, 1967
18J282724 => 1 =(2nd half of body style, can only be 11 2-door sedan)
18J282724 => 8 =1968
18J282724 => J = Janesville, Wi (Passenger model)
18J282724 => Passenger model begins with 100001 so that also holds true.

Now for the ??? Are you sure its TI0I6TH? That's the only one I can't find in Colvin. I found an IH for the 390 hp 427 cid passenger model with manual (1968), but the 390 HP version was only a 2-bolt block.

JChlupsa · #3 02-19-2004, 03:44 AM

18J282724 => 1 =(2nd half of body style, can only be 11 2-door sedan) 1 = Division- in this case Chevrolet

One of the last of that block put out also since it was stopped being used in Jan of 68. All the rest checks out.

Pantera · #4 02-19-2004, 03:45 AM

How could that be a Alum block? I thought the ZL-1 blocks came out in '69?
Sounds more like a alum head L-88 motor but I was not aware that they put them in a Pass car back in 1968 according to the vin #?? That is a '68 S/N is it not?

GMH454 · #5 02-19-2004, 08:56 PM

Glad you asked it. Its been puzzling me.

jg95z28 · #6 02-20-2004, 02:51 AM

You guys are right. If those numbers are correct it is indeed a cast iron block.

JChlupsa · #7 02-20-2004, 03:38 AM

John Z says its a out of a 68 Caprice from the Janesville plant

**rpoz11** · #8 02-21-2004, 05:46 PM

As far as Im aware of there are 3 BB aluminum casting numbers but I still am searching to see if there are any "0" code prototypes ever made. Im in conversations with my NCRS judge friend trying to eventually document these. RoadCourse and 1/4 mile guys to me are where I find these and occasional Marine shops Ive seen these at. Ill keep digging until Im exhausted on my searching...

Also, as there were a few Small Block GM aluminum castings; Is there any Board knowledge of those #'s?

**KNAPPY** · #9 02-21-2004, 06:51 PM

What kind of numbers would an "o" block have?

**rpoz11** · #10 02-21-2004, 06:53 PM

0-123456 This would be what GM did when making Prototype pieces; This was there way of Identifying non-DOT parts manufacturing.

Dedicated to the Promotion and Preservation of American Muscle Cars, Dealer built Supercars and COPO cars.