1966 327-300hp Oil dipstick tube

[Larry M.]

I have 2 GM numbers for my upper engine oil dipstick tube. My assembly manual says 3876784 with a note next to it that I can't make out. and doing research, I'm getting another GM number which is 3865664. Does anyone have info on this tube? Thanks Larry.......

[John H.]

Re: 1966 327-300hp Oil dipstick tube

I have 2 GM numbers for my upper engine oil dipstick tube. My assembly manual says 3876784 with a note next to it that I can't make out. and doing research, I'm getting another GM number which is 3865664. Does anyone have info on this tube? Thanks Larry.......

Larry -

3876784 is the correct tube; Paragon and LICS have the correct reproduction.

[Larry M.]

Re: 1966 327-300hp Oil dipstick tube

Larry -

3876784 is the correct tube; Paragon and LICS have the correct reproduction.

Thank you John
Larry....

[Joe L.]

Re: 1966 327-300hp Oil dipstick tube

Thank you John
Larry....

Larry------


The difference between the tubes is that the original tube had a reduced diameter ("swaged down") upper end whereas the replacement did not. Both tubes will function perfectly, though.

[Larry M.]

Re: 1966 327-300hp Oil dipstick tube

Larry------


The difference between the tubes is that the original tube had a reduced diameter ("swaged down") upper end whereas the replacement did not. Both tubes will function perfectly, though.

Thanks Joe.
Larry.......

[John H.]

Re: 1966 327-300hp Oil dipstick tube

Larry------


The difference between the tubes is that the original tube had a reduced diameter ("swaged down") upper end whereas the replacement did not. Both tubes will function perfectly, though.

Joe -

Believe it or not, the reproduction also has the correct swaged upper end, although the GM replacement did not.

[Larry M.]

Re: 1966 327-300hp Oil dipstick tube

Thanks again John.
Larry........

[David L.]

Re: 1966 327-300hp Oil dipstick tube

The 3876784 upper dipstick tube was used on the following models:
1966 Pass., Corvette (283,327)
1967-1972 Corvette (327,350)

The 3876784 tube also serves as a replacement for the 3860319 tube used on the 1965 Pass., Corvettes (283,327) models.
The 3876784 tube measures about 0.43" in diameter except the top 2" section which is narrower and measures about 0.38" in diameter. The total length of the tube measures about 9 3/4" on the arc and about 9 1/2" on the chord (straight line from end to end).

The 3876784 tube was discontinued in July 1974 and replaced with tube # 3865664 which was used on 1965-1966 Chevrolet trucks Ser. 10-30 (283,327) but the 3865664 tube must be cut 1/4" from the top end when used on 1965-1966 283 & 327 Chevrolet passenger & Corvette models. The 3876784 and 3865664 are noticeably different in appearance.

The 1967 Chevrolet (283,327) tube, GM # 3900428, is almost identical to the 3876784 tube but measures about 1/8" shorter in length.

I can provide a photo of the various tubes for comparison purposes, if necessary. All the tubes that I have are original GM both used and NOS. I do not have a 1965 tube, GM #3860319, in my collection.

[Henry S.]

Re: 1966 327-300hp Oil dipstick tube

Larry,
Last year I was still able to get the upper tube for my 67 327/300 from Jackson Chevrolet (our local dealer) in Sullivan, Illinois. I ordered 2 at the time and still have one unwrapped. When I head to the shop after lunch I'll check the number and also see if it does or doen't have the swaged end Joe and John mentioned. Even though the Chevrolet dealer has been in existance for quite awhile I doubt the ones I have were sitting on the shelf and probably are the GM replacement Joe talked about.

John since I'm assuming mine is the GM replacement and very likly doesn't have the swaged upper end to be correct would we want the LIC or Paragon replacement instead? Thanks.

[John H.]

Re: 1966 327-300hp Oil dipstick tube

John since I'm assuming mine is the GM replacement and very likly doesn't have the swaged upper end to be correct would we want the LIC or Paragon replacement instead? Thanks.

Henry -

It only matters for judging; they'll expect to see the swaged upper end on the tube. Functionally, it makes no difference.

[David L.]

Re: 1966 327-300hp Oil dipstick tube

The GM replacement tube (GM # 3865664) is 1/4" longer than the original 3876784 tube. It states right in the 1975 and newer Chevrolet parts catalogs that the 3865664 tube must be cut 1/4" at the top end when using to replace the 3876784 tube. I have several original 3876784 tubes from 1966 Chevrolet 283 & 327 models as well as a couple of NOS 3865664 tubes and the difference in length is 1/4".

Dave

[Timothy B.]

Re: 1966 327-300hp Oil dipstick tube

Now that we are talking about the upper dipstick tube, can anyone provide a picture of the correct original tube for my 63 300hp engine. I want to compare with what I got from GM twenty years ago.

My 63 tube is not narrowed at the top and the felt fits nicely to seal the dipstick. I will look through receipts for the part #.

[Henry S.]

Re: 1966 327-300hp Oil dipstick tube

The GM replacement tube (GM # 3865664) is 1/4" longer than the original 3876784 tube. It states right in the 1975 and newer Chevrolet parts catalogs that the 3865664 tube must be cut 1/4" at the top end when using to replace the 3876784 tube. I have several original 3876784 tubes from 1966 Chevrolet 283 & 327 models as well as a couple of NOS 3865664 tubes and the difference in length is 1/4".

Dave

So with one of the GM replacements if it's not cut off you're running too much oil at the FULL mark?

[David L.]

Re: 1966 327-300hp Oil dipstick tube

So with one of the GM replacements if it's not cut off you're running too much oil at the FULL mark?

Yes, the "A" and "B" dimensions on the 3862730 dipstick are 20 5/32" and 20 59/64" according to my 1966 Chevrolet parts catalog . The difference would be 49/64" (0.77") which I assume would represent 1 quart. Therefore 0.25" on the dipstick would represent 0.25/0.77 or 0.32 quart.

[David L.]

Re: 1966 327-300hp Oil dipstick tube

The 1963-1964 upper dipstick tube is GM # 3826074 and was replaced with tube # 3732488 in Sept. 1974 (over 36 years ago). The 3732488 tube was original equipment on 1957-1962 Corvettes. I have 3 NOS 3732488 tubes in my collection but no 3826074 tubes. The 3826074 and 3732488 tubes must be the same length as the 1958-1963 Corvettes used the same dipstick (GM # 3739830) although the markings on the 3739830 dipstick vary from year to year as there were at least 3 different vendors ("B", "M", and "E" markings).

My guess is that the 3732488 and 3826074 tubes were exactly the same EXCEPT the 3826074 was painted black and the 3732488 was plain metal. I did some research on the 1963 dipstick and tube back in the late 1980's and I found no difference between the two tubes except for paint. Andy from N.J. might know the correct answer.