X on the front of a 409 engine block - Impala Tech
Tag Team De-coding tags & numbers

LinkBack Thread Tools
post #1 of 3 (permalink) Old 02-20-2014, 08:35 PM Thread Starter
Join Date: Jan 2014
Location: Arizona
Posts: 17
X on the front of a 409 engine block

Hi from Arizona Jim. During my last thread on decoding my 64 SS it seems I read somewhere that a 409 engine has an X on the front of the engine block, driver's side, below the head. Maybe I read it here or maybe in one of the magazines I have been adding to my library. Mine has an X. At the January auctions here in Scottsdale I checked 409s for the X and found a 64 that did have it and a 63 that didn't. Then a guy heard me talking about the X and he said not all 409s had the X. Another theory I 've heard is that the X indicated a warranty engine (mine is not a warranty engine it is the original). I contacted Glenn at Hagerty Insurance and he couldn't find any information about the X on the block in their library of info (Glenn is their guy in the advertisement about hard to find information - very nice person by the way). He hypothesized that maybe it was insignificant; maybe indicating a shift change. I doubt their were 2 castings for 1st and 2nd shift. So what's the deal? Wherever the answer is I'd love to get a copy of the book or document about the X. Thanks guys. My 64 is in the photo showroom identified as Mike and Jim's 64 Impala.
Jim V. is offline  
Sponsored Links
post #2 of 3 (permalink) Old 02-20-2014, 09:25 PM
Join Date: Jan 2006
Posts: 12,381
The X was added to the block to distinguish a car 409 engine from a truck block that had lower compression. Also during the closing years of the 409's production the factory addressed complaints of owners taking their 409 in for repair because they missed a shift at 8,200 and it over reved.

Great story but when the tech who took the 409 back to his shop (because that was a perk of line tech's that they could selflessly step forward to claim an engine to destroy it on behalf of Chevrolet). Back then the factory had the dealership throw warranty claim engines in the dumpster, or other wise destroyed them (interpreted by the techs to mean not as being not available for resale until they were rebuilt).

Because back then Chevrolet didn't want the motor back (it cost more to ship than it was worth) the tech got it. He took it home and pulled the heads off only to discover that the 409 they had warranted was in fact a 348. Even an experienced tech and a warranty claim officer can not tell if a 409 is a 348 except by the oil dip sticks location. Unfortunately $37 bought you a 409 oil pan and oil pump pick up. (there were other indicators but who would suspect an honest customer?)

Hence the factory getting wise and marking the 409 blocks toward the end of the production run with a very visible X (if they had done the same thing with the 427 block it would have saved me a fortune in money spent on 396 motors that I bought with a 427 decal on it that you could buy for $3.85). It also gives you an idea how far back people have been pulling oil pan swaps, and restamping of cheaper less desirable blocks (the 348 wasn't stamped with a VIN, but the 409 was).

Big Dave

Last edited by Big Dave; 02-25-2014 at 08:16 AM. Reason: typi fron fat fingers
Big Dave is offline  
post #3 of 3 (permalink) Old 02-24-2014, 11:50 PM Thread Starter
Join Date: Jan 2014
Location: Arizona
Posts: 17
Once again Big Dave you've answered my question. Thank you very much. Arizona Jim
Jim V. is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Impala Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome