Midyear small block Carburetor to Intake Manifold studs - Are these originals?

[Joe L.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

Tim,

The AIMs call out the same GM 120368 part number for the carburetor nut from 1963 through at least 1969. In the '67 AIM, this same Nut part number is also called out for the unidentified fan clutch to fan blade studs, and also secures the hose clip to the front of the A6 compressor.

FWIW, AMK shows this part number as being 5/16-24, Grade 5, 1/2" across the flats, .27 thick. Their photo shows what appears to be a standard height hex nut.



Edit: just saw Joe's post, looks like AMK has this one right.

Scott-----


By the way, GM specifications for most nuts have an allowable range for the various dimensions. So, I would not expect every GM #120368 nut to measure exactly 0.270" thick.

[Scott S.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

Scott,

I have collected many original carb studs from Chevrolet and Corvette intakes over the past 30+ years but mainly in the 1980's. All I could EASILY find are the studs pictured below.

Early 1963 300 HP C.I. intake, cast. # 3799349 dated K122 (Nov. 12, 1962),
measured 1.77" OAL, 0.50" long coarse threads, 0.97" long fine threads, "dimple" on bottom end.

Early 1966 B.B. C.I. intake, cast. # 3866948 dated I245 (Sept. 24, 1965),
measured 1.31" OAL, 0.45" long coarse threads, 0.54" long fine threads, "dimple" on top end.

Dave

Thanks for the pictures Dave,

It looks like they made these carburetor studs both ways, in which case the 'dimple' or lack thereof on the nut-end of the stud should not be a determining factor regarding originality.

[Gary S.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

If you have a 67 L79, you are safe with those studs from what I have seen over the years. I have had lots of 67's and have 3 now including a tri-power and L79. The carb studs are the same on both cars, so appear to be standard for a Holley carb. Both 1 5/16 long and a hollowed end on the bottom and dimple end on the topside.

[Scott S.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

If you have a 67 L79, you are safe with those studs from what I have seen over the years. I have had lots of 67's and have 3 now including a tri-power and L79. The carb studs are the same on both cars, so appear to be standard for a Holley carb. Both 1 5/16 long and a hollowed end on the bottom and dimple end on the topside.

Gary,

Thank you very much for the info and pictures,

Scott

[David L.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

Scott,

While looking for some other parts I came across the following original carb to manifold studs:

Early 1969 3927184 CI intake dated G98 (July 9, 1968)
measured 1.33" OAL, 0.45" long coarse threads. 0.67" long fine threads, no dimple

1958 3746829 C.I. intake dated E 28 8 (May 28, 1958),
measured 1.50"-1.56" OAL, 0.50" coarse threads, 0.84" fine threads, no dimple

Dave

[Scott S.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

Dave,

Thanks very much for remembering the Thread and taking time to post the measurements!

[David L.]

Re: Midyear small block Carburetor to Intake Manifold studs - Are these originals?

Scott,

As usual I found some more of my intake studs while looking for other parts. Photos are in the link below.

3866948 C.I. BB (Holley), I245 (Sept. 24, 1965)
O.L. = 1.32", fine thread length = 0.60"+/-, coarse thread length = 0.48"+/-

3872783 C.I. SB (Holley) B46 (Feb. 4, 1966)
O.L. = 1.52", fine = 0.80"+/-, coarse = 0.50"+/-

3875952 C.I. SB (Rochester) E106 (May 10, 1966)
O.L. = 1.54", fine = 0.88"+/-, 0.54"+/-

N.O.S. GM # 382919
O.L. = 1.25", fine = 0.52"+/-, coarse = 0.52"+/-

Dave

http://imgur.com/a/3gFaX#0