Block ID

[farhaud]

Hi. I was checking into the validity of my 1968 Corvette and the possibility that it's an L88 or not. The block ID says 3970040. I don't see this number on your tech site. Can someone give me some info on this block? Specifically, I'm looking for what L number it is, what ci and horse power it may be, etc. If it helps, the VIN is 194378W420022.

Thanks for your help.

 

[silver77vette]

Looked up the number you gave in my Corvette restoration guide. The closest is 3970010, which is shown as late 350 in 1969.Was used in 69 through 80. It does not show your VIN. 1968 VINs are shown as 194378S400001-194378S428566. Good luck.

 

[Tom73]

Cannot find any record for a 3970040 block. If it is an '010 block, as Silver77Vette said, then it is a 350 which would mean that it is not the original engine in your 68 as the 68 used a 327. Post the numbers on the stamp pad, machined surface on the block in front of the passanger side head, and we should be able to tell you what the block was originaly.

By the way, that "W" in your VIN should be an "S". It represents the St Louis plant.

tom...

 

[mike weyman]

3970010 is the code for the high nickle 350 block. the number 1 is distorted on my block ( looks like casting flash )my loonie says that it is a 1 not a 4 . my block has the matching # heads and the right block. check the head cast # if it's 333882 it's the right heads for the 010 block. the valves are 2.02/ 1.65 for the l82 1.95/ 1.6 valves for the l48

 

[JohnZ]

Over seven million 3970010 350 blocks were made from 1969-1980, used in all cars, trucks, and service replacement applications, and less than 1% of them were "high-nickel"; 22 different cylinder heads were used with that block, and the 333882 smog heads were only used for the Corvette application from '73-'77.

BTW, if that '68 VIN plate really has a "W" in the middle, you have a problem.

 

[Vettehead Mikey]

If you're looking in the 'normal' place for a date code but can't find one, there's a chance that your block was cast at the McKinnon foundry in St. Catherines Ont.

Is there anything stamped on the pad directly in front of the passenger side cylinder head?

 

[Billybeau1]

BTW, if that '68 VIN plate really has a "W" in the middle, you have a problem.

JohnZ & Mikey, I was doing a search on head numbers and came across this thread that died last Sept. Looks like you scared this guy away

BTW - Where is the head number stamped on a 74 ? I know my engine is original but I suspect the heads are not. Any way to tell for sure?

Thanks

 

[Hrtbeat1]

JohnZ & Mikey, I was doing a search on head numbers and came across this thread that died last Sept. Looks like you scared this guy away

BTW - Where is the head number stamped on a 74 ? I know my engine is original but I suspect the heads are not. Any way to tell for sure?

Thanks

Billy here is a site that will give you a lot of info on block and head casting numbers. www.mortec.com

 

[JohnZ]

The casting number and date is normally cast-in between the center cylinders - just pull the rocker covers and it'll be visible; it'll look like this:

 

[Billybeau1]

Thanks guys

 

[Vettehead Mikey]

'74 Corvette heads are 333881 or 333882 for L48, 333882 for an L82 and 336781 for the LS4.

 

[Billybeau1]

Thanks Mikey. I will check soon. The reason I suspect the heads are not original is before I painted the engine the heads were blue. Kinda like pontiac blue. Oh well, I'll check for sure soon. Thanks again everyone

 

[Hrtbeat1]

The casting number and date is normally cast-in between the center cylinders - just pull the rocker covers and it'll be visible; it'll look like this:

Nice set of heads there John. I've got a set of 3890462's sitting in the shop I need to do something with. BTW your cast date is May 23rd of 1967, but I'm sure you knew that already.

 

[JohnZ]

Yup, they're original, as is all the rest of the drivetrain.