63-64 Upper Dipstick Tube 3826074

[David L.]

I have been trying to figure out the difference between the 1963-1964 upper dipstick tube (GM # 3826074) and the 1957-1962 tube (GM # 3732488) since the late 1980's when I owned a 1963 split window coupe (VIN # 1450). GM # 3826074 was discontinued in Sept. 1974 and replaced with GM 3732488.

Pictured are an original 3732488 tube on top and what I believe to be a 3826074 tube on the bottom (from a swap meet). The basic difference is the bottom tube measures about 1/8" longer then the 3732488 tube.

All base engine 1963-1974 Corvettes used the same oil pan (GM # 3820000).

The 1963 used a 3739830 dipstick (A = 19 9/16" or 19.56", B = 20 21/64" or 20.33") and 3826074 upper tube (length to be determined).

The 1966 used a 3862730 dipstick (A = 20 5/32" or 20.16", B = 20 59/64" or 20.92") and 3876784 upper tube (total L = 9 7/8", effective L = 9 1/8" or 9.13"). I have several original 3876784 tubes in my collection.

Below is my calculation for the effective length of the 3826074 upper tube:

1966:
Using "A", 20.16" - 9.13" = 11.03" (surface of block to "FULL" in oil pan)
Using "B", 20.92" - 9.13" = 11.79" (surface of block to one quart low)

1963:
Using "A", 19.56" - 11.03" = 8.53" (effective length of upper tube)
Using "B", 20.33" - 11.79" = 8.54" (effective length of upper tube)
Rounded off the effective length of the 3826074 upper tube should be about 8 1/2" and the total length would be 3/4" longer or 9 1/4".

Does anyone have an ORIGINAL 1963-1964 upper dipstick tube (GM # 3826074) to verify my theory and that the bottom tube in my photo is an original 3826074 tube.

Dave

[Doug L.]

Re: 63-64 Upper Dipstick Tube 3826074

Hi David,
My tube ('64 L-84) is installed and covered by the plug shield and ignition shield. I'm not willing do all that would be necessary to pull it out of the block so I can't get overall measurements, but from the upper end of the tube to the top of the flair where the tube enters the block measures ~8-5/8". That more or less fits with your calculations.

Doug

[David L.]

Re: 63-64 Upper Dipstick Tube 3826074

Doug,

I do NOT recommend removing the upper dipstick tube from your engine.

The direct measurement from the top of the "stop" to the top of the tube are as follows:
3732488 tube measures 7 7/8"
3826074??? tube measure 8"

Dave

[David L.]

Re: 63-64 Upper Dipstick Tube 3826074

Doug,

Pictured is an original 3876784 tube (66-67 Corvettes as well as other models). The O.D. = 0.44" but the top 2" section measures 0.38" O.D. The measurement from the top of the "stop" to the top of the tube is about 8 1/2".

Dave