O-Ring Seal Dimensions for Big Block and Turbo 400 Dip Stick Tubes

[Rocco S.]

I'm working on a 1968 Big Block with a Turbo 400 trans.

I need to replace the O-Ring seals on both the engine and trans dipstick tubes. I believe the GM numbers are as follows:

GM# 274244 Engine Dipstick Tube
GM# 1164253 Turbo 400 Dipstick Tube

I was hoping someone would have the dimensions (ID, OD, Thickness) and/or the commercial #s for these. I think these are probably commercial dimension O-Rings, with GM#s since they would not design a special O-Ring for such simple applications.

I found the first one on Amazon but don't want to pay $15.00 for a single O-Ring.

Any help would be appreciated.

Thanks
Rocco

[Joe L.]

I'm working on a 1968 Big Block with a Turbo 400 trans.

I need to replace the O-Ring seals on both the engine and trans dipstick tubes. I believe the GM numbers are as follows:

GM# 274244 Engine Dipstick Tube
GM# 1164253 Turbo 400 Dipstick Tube

I was hoping someone would have the dimensions (ID, OD, Thickness) and/or the commercial #s for these. I think these are probably commercial dimension O-Rings, with GM#s since they would not design a special O-Ring for such simple applications.

I found the first one on Amazon but don't want to pay $15.00 for a single O-Ring.

Any help would be appreciated.

Thanks
Rocco

Rocco-----

The GM #274244 is GM-discontinued. Its dimensions are:

OD----0.490"

ID----0.334"

thickness----0.067"

I do not have specs on the GM 1164253. However, it was discontinued by GM in November, 1985 and replaced by GM #6264902. The latter remains available from GM for $2.54 GM list.

Whether either of the above are identical to commonly available o-rings, I do not know. However, neither was ever carried by GM in "Standard Parts"; they are both group-specific.

[Ed S.]

Rocco,

I'm also starting to research sources for the GM #274244 engine dipstick tube O-Ring for a 1969 BB and the only direct replacements I've found so far also are being offered for sale at $15+....which I also don't plan to pay for a single O-ring.

However, I've found a NAPA 727-2011 O-ring that measures OD=0.4375" // ID=0.3125" // Thickness = 0.0625" and sells for less than a dollar. While the dimensions aren't an exact match, I've been told that others have successfully utilized this O-ring for a BBC dipstick. I'll likely take a chance on this O-ring when I get to that point unless I'm able to find a more reasonably-priced original.

Cheers,
Ed

[Rocco S.]

Ed,

Thanks for the info on the NAPA O-Ring. I found a similar size in my O-Ring selection set. The set is large with both small and large thickness O-Rings. I'll try one first.
Now, I need to go to my Chevy dealer and order the O-Ring for the Turbo 400.

[Owen L.]

Apparently the 6264902 transmission o-ring is also used in a main bearing cap on Gen V and VI big blocks. Googled dimensions on it and the specs on it are - 0.565 in Inside Diameter - 0.77 in Outside Diameter - 0.1 in Thick - Rubber - Black - Rear Main Seal