Small Block Timing Cover ID Help?

[John H.]

Re: Small Block Timing Cover ID Help?

Does anyone have a 1967 Corvette small-block timing cover dated "13 66" or later?

Scott -

It's been my experience on many '69 Z/28's that the timing cover date format is month-year(i.e., 2 69, 7 69, 12 69, etc.). Oddly, not ALL of them were dated - some were not. My engine was built in mid-January, and the cover is dated "1 69", and I have a spare taken off a May-built 302 engine, and it's dated "4 69".

[David L.]

Re: Small Block Timing Cover ID Help?

Scott -

It's been my experience on many '69 Z/28's that the timing cover date format is month-year(i.e., 2 69, 7 69, 12 69, etc.). Oddly, not ALL of them were dated - some were not. My engine was built in mid-January, and the cover is dated "1 69", and I have a spare taken off a May-built 302 engine, and it's dated "4 69".

John,

If that is true what is the month of Eric's timing cover stamped "27 69" and my 69 Z28 timing cover stamped "33 69"? I also have the same timing cover on my 1970 Camaro SS350 engine stamped "19 70" (19th week of 1970). As far as I know there are only 12 months in a year. Using my theory your timing cover dated "1 69" (1st week of 1969) would match up with a mid-January 1969 engine and your "4 69" cover (4th week of 1969) would also be correct for a May 1969 engine. I believe that timing covers like many other parts were made in large batches and then stock piled for later use. I guess more examples are needed.

It is POSSIBLE that when timing covers were first date coded starting with the 1967 model year (Fall of 1966) the system was by the month & year but in the 1969 & 1970 model years I firmly believe that the date code system was by the week & year.

Dave

[David L.]

Re: Small Block Timing Cover ID Help?

The 69-70 Chevrolets & Corvettes w/350 engines & 8" balancers used timing cover # 3946870 (Gr. 0.206) as per my 1969 Corvette parts catalog (Sept. 69), 1969 Chevrolet parts catalogs (Oct. 68 and May 69), 1969 Corvair-Chevy II-Chevelle-Camaro parts catalogs (Oct. 68, Oct. 69, and Apr. 70), 1970 Chevrolet parts catalogs (Sept. 69, Oct. 69, Jan. 70, and Oct. 70), and 1971 Chevrolet parts catalogs (Sept. 70 and Jan. 71).

GM # 3946870 was discontinued in June 1971 and replaced with GM # 3991433 which used a "bolt on" tab (either 3991435 or 3991436) depending on the balancer size.

Enclosed is a picture of a 3946870 cover stamped "19 70" (19th week of 1970) on the left.

The 71-73 Z28 & SS350 models w/8" balancer used a different timing cover, picture on right, as per information I found on the Nasty Z28 website. I assume the 71-73 Corvette (350) models used the same cover but I am not really sure. This cover is stamped "33" (33rd week, I assume) but without any year stamping. Note the shortened indentation where the "33" stamping is located. I do not believe that this 71-73 cover was ever sold "over the counter".
It was serviced with the 3991433 cover (without the tab).

There were several 8" balancers used from 1969-1971:
3947704, 69-71 Chev. models & Corvette (350) 300HP
3947708, 69 Z28 (302)
3947712, 69-71 Corvette (350) w/HP & SHP, 70-71 Chev. models (350) w/SHP
These balancers were stamped with the last 4 digits of the part number (7704, 7708, and 7712) and I believe that they were date coded.

[Joe L.]

Re: Small Block Timing Cover ID Help?

John,

If that is true what is the month of Eric's timing cover stamped "27 69" and my 69 Z28 timing cover stamped "33 69"? I also have the same timing cover on my 1970 Camaro SS350 engine stamped "19 70" (19th week of 1970). As far as I know there are only 12 months in a year. Using my theory your timing cover dated "1 69" (1st week of 1969) would match up with a mid-January 1969 engine and your "4 69" cover (4th week of 1969) would also be correct for a May 1969 engine. I believe that timing covers like many other parts were made in large batches and then stock piled for later use. I guess more examples are needed.

It is POSSIBLE that when timing covers were first date coded starting with the 1967 model year (Fall of 1966) the system was by the month & year but in the 1969 & 1970 model years I firmly believe that the date code system was by the week & year.

Dave

Dave------


One thing to keep in mind here is that Chevrolet was using the basic timing cover stamping by the millions. It's very possible that they had 2 or more suppliers for the basic stamping and those suppliers might have used different date stamping nomenclatures.