Engine code or date code?
 

Question, my 1969 396 engine has the following stamp on the passenger side: 10 21 YS , is this a date code ?


Thanks !

Re: Engine code or date code?
 

the casting date is on the back of the block near the bellhousing flange on the passenger side and its cast into the block not stamped.

I think what your posting is the front pad code, YS comes up as a 69 Truck motor.

Re: Engine code or date code?
 

Thanks !

Re: Engine code or date code?
 

10 21 is the engine assembly date- October 21
YS suffix code is for a 1969 396 truck engine, 310hp, 4bbl carb, manual transmission
There should be a letter at the very beginning of the stamped code that will tell you the engine factory.
F- Flint, MI (1955-1966)
V- Flint, Mi (1967 and newer)
T- Tonowanda, NY
K- St. Catherine, Ontario
S-Saginaw, Mi
M- Mexico

The date cast into the block is the date when the block was cast and which shift it was cast on.

Re: Engine code or date code?
 

thanks !

Re: Engine code or date code?
 

I don't think they stopped using F for Flint built engines in 1966, they just added a second production line to keep up with demand in 1967 = V.
I have 292 blocks from '67 and '68 that have F codes in the stamped dress numbers.

Re: Engine code or date code?
 

That came right from The Lime Book as my source.http://www.camaros.org/pdf/LimeBook.pdf

Re: Engine code or date code?
 

Then theres this chart from Inliners International, its not clear if the six cylinders remained F and the V8's changed to V. The Lime Book only covers V8's.
https://www.inliners.org/ubbthreads/...t&Number=66011

Re: Engine code or date code?
 

I've never seen an L6 with a 'V' engine dress digit, but then I have not seen every L6 ever built. My three 292s were all built on the F Line. One a '63 Core, a '67 I ran from 1977 to 2002, and the OEM '68, that came in the truck when I bought it in 1973. I put it up in crates in 1977 and rebuilt it in 2005.

Re: Engine code or date code?
 

The Lime book is good, but some info is not 100 percent correct. For example, the engine code on my Blazer's 1970 350 4 speed is:

V0223TBC

V Flint

0223 February 23, 1970

TBC is listed in that book as a 1970 350/255BHP 4 barrel carb truck engine with a 3 speed manual trans.

Re: Engine code or date code?
 

Continuing to go off topic from the OP's original question..
Looks like https://www.nastyz28.com/gm-chevy-co...s-suffix-6.php is incorrect as well then even though it shows it as MT, 3 spd.
If there are better sources for this information feel free to post it up. The GM book simply shows Manual transmission, does not specify 3 speed or 4 speed. http://www.gmpartswiki.com/getpage?pageid=21050

The GM P&A catalog does not specify the change from F to V or addition of V to the engine plant identifier. The things I've seen that is common among these sources (Lime Book and nastyZ28) is F is Flint (Motor) and V is Flint (Engine). Also, the Lime Book is only V-8's, no mention of 6 cylinders and I guess I didn't say that applied to 6's either. Its possible the 6's kept the F prefix, we all know there are many other nuances with these trucks that don't seem to follow logic or are well documented.

Re: Engine code or date code?
 

Do you think the folks with 2024 pickups will be sleuthing like this in 50 years .