Correct big block oil dip stick

[Steve Antonucci]

Hello everyone,

In the quest for original "correct" components for my 68 & 69 big block
engine restorations, oil dip sticks & tubes are usually on the list, but
I often end-up settling for what is available. I'd like to change that.

Can any of you share the following:

1) What distinguishes an original or NOS big block ( BB )oil dip stick from

repro or service parts? Do they look different?
2) What distinguishes an original or NOS BB oil dip stick tube

from repro or service parts? Bends, welds, etc.?
3) I've seen red, pink, yellow, etc. plastic tips of BB dip sticks in the

past. What colors are correct for what applications/years? I'm

primarily interested in 1967 to 1970 BB applications.

Can any of the members share their valued opinions?

Thanks for the great - steady stream of information on this forum!
Valuable beyond words!
Steve

[Joe L.]

Re: Correct big block oil dip stick

Steve-----

Generally, original 65-69 big block dip sticks had a somewhat longer "shank" section of the handle between the loop and the tube cap than do later or replacement dipsticks. Also, the "loop" for the handle had more of an open space than later or replacement dipsticks and the loop was more "round". In addition, original 63-69 did not have the "indention" on the handle shank section.

There were 4 dip sticks used for 1965-74 Corvettes. 1965 to 1967 used dipstick GM #3860316. This dipstick had a pink or "salmon" colored button. It measured 17-13/32" from the tube seat to the "full" mark and 23/32" from the "full" mark to the "add" mark.

The 1968 through early 1969 dipstick was GM #3925520. This dipstick may also have been used for very late 1967 big blocks, as well. This dipstick had a "white" button. It measured 17-13/32" from the tube seat to the "full" mark and 1-3/32" from the "full" mark to the "add" mark.

Most of 1969, as well as, possibly, very early 1970 used dipstick GM #3959158. I'm not sure what color that the button on this dipstick was. It might have been white, red, or green. This dipstick measured 17-13/32" from the tube seat to the "full" mark and 1-19/32 from the "full" mark to the "add" mark. This particular dipstick was only available in SERVICE for a very limited period of time---from about December 1968 through November, 1970.

ALL of the above dipsticks use dipstick tube GM #3870324. This tube is more-or-less straight in configuration. I don't have the length, at the moment.

Beginning in very early 1970, if not from the very beginning of the model year, the Corvette dipstick changed to GM #3981088. This was used until the end of C3 big blocks in 1974. The button on this dipstick was red. This dipstick has a length of 23-13/64" from the tube seat to the "full" mark and 51/64" from the "full" mark to the "add" mark.

The above-referenced dipstick is used in conjunction with dip stick tube GM #3981089. This tube has a pronounced curve in it and is 22-5/8" long. The earlier dipsticks cannot be used with this tube and the 3981088 dipstick cannot be used with the earlier tube. Earlier big block applications can be SERVICED with this dipstick and tube if they are used as a SET.

For 1968-69, reportedly there was a longer dipstick and longer dipstick tube used for 427 with A/C applications. If so, this tube and dipstick were never available in SERVICE but, if they existed, I would expect that their configuration was similar to the 70-74 dipstick and tube. The GM #3981088 and 3981089 did not exist in 1968, though, so if the longer style tube was used for A/C applications, then there must have been a predecessor part number.

Another question which may come out of this is: if the configuration of the 65-69 oil pans was, essentially, the same (which it DEFINITELY was) and if the same dipstick tube was used for 1965 through 1969 (which it DEFINITELY was), then how come the distance between the "full" and "add" marks had 3 different measurements between 1965 and 1969? That's a good question and I don't have an answer for it.