67 300hp balancer date code

[John S.]

Need some help after looking thru the archives. Have taken my 35,000 mile 300 horse oil pan and timing chain cover off to fix oil leaks and replace the original plastic timing gear. Everything I touch is date coded correct (and I believe original to the car. Body build date E29, car birth date January 2nd or 3rd depending on first day back after new year. Everything is December (12 or L) except the flywheel which is November (K) and I believe the balancer. Balancer is stamped on the outer ring (inside next to timing chain cover with
K F 6. Looked at it with a loop and am fairly certain of the code. Does not match any thing I have read in the archives which range from "no stamping" to regular date code stamping. ie:K 12 6 for a November 12 66 code. Also, the timing chain cover just has a 12 66 stamped on it. Any ideas?

[Joe R.]

Re: 67 300hp balancer date code

Need some help after looking thru the archives. Have taken my 35,000 mile 300 horse oil pan and timing chain cover off to fix oil leaks and replace the original plastic timing gear. Everything I touch is date coded correct (and I believe original to the car. Body build date E29, car birth date January 2nd or 3rd depending on first day back after new year. Everything is December (12 or L) except the flywheel which is November (K) and I believe the balancer. Balancer is stamped on the outer ring (inside next to timing chain cover with
K F 6. Looked at it with a loop and am fairly certain of the code. Does not match any thing I have read in the archives which range from "no stamping" to regular date code stamping. ie:K 12 6 for a November 12 66 code. Also, the timing chain cover just has a 12 66 stamped on it. Any ideas?

Hi John:

My 300 HP engine was assembled on March 17, 1967. The timing cover is stamped "3 67" which I'm sure means March 1967. The balancer is stamped "F B 7" on the outer face of the hub (note this is a different location than what you report). I'm not sure how to decode the "F B 7" marking, but I suspect that the "7" is for 1967.

On a related note, be sure to replace your rear main seal and the timing cover seal as part of your project. Also check the balancer surface for a wear ring where the seal contacts it.

There is plenty of good info in the archives from Joe Lucia about the best seals to use and the balancer repair ring. Contact me offline if you want more details. I used the seals Joe Lucia recommended and bought a new GM balancer that he recommended. Absolutely no leaks!