63 and 64-67 Starter Bolts

[David L.]

The starter bolts for 63 and 64-67 Corvettes are listed in the assembly manuals and vintage parts catalogs as follows:

63 long bolt: GM # 3815338, 3/8"-16 X 4 21/32"
63 short bolt: GM # 3795470, 3/8"-16 X 1 5/16 with uses Sp. Washer # 3765135 (13/32" I.D. X 11/16" O.D. X 3/32" thick)

64-67 long bolt: GM # 3830134, 3/8"-16 X 4 21/32"
64-E65 short bolt: GM # 3849418, 3/8"-16 X 1 27/32"
L65-67 short bolt: GM # 3880880, 3/8"-16 X 1 27/32"

GM # 3815338 was replaced by GM # 3830134 in Oct. 1963 as per Chevrolet Parts History (service parts).
GM # 3795470 was replaced by GM # 3830135 in Oct. 1963 as per Chevrolet Parts History (service parts).
GM # 3830135 does not appear in the 63-67 assembly manuals.
GM # 3849418 was replaced by GM # 3880880 in 3/31/65 as per 1965 AIM and Chevrolet Parts History (service parts).

Attached below in the photos are 65-67 Grade 8 starter bolts on the left with "RBW" on the long bolt and "C" on the short bolt. On the right side are two Grade 5 starter bolts with "M" on both bolts that match the lengths of the 65-67 bolts. I believe that the long "M" bolt might be a 63 long bolt, GM # 3815338, but the short "M" bolt might be GM # 3849418 as it is 17/32" (0.53") longer that a 63 short bolt.

Question: Were the 63 starter bolts (GM # 3815338 & 3795470) and the 64 starter bolt (GM # 3849418) grade 5?

The 65-67 starter bolts (GM # 3830134 & 3880880) seem all to be grade 8. I have several sets of these grade 8 starter bolts marked "RBW" and "C" from 65-67 Chevrolets in salvage yards.

Dave

[Alan D.]

Re: 63 and 64-67 Starter Bolts

My Mar64 car has RBW, grade 8 Most everything on it are original.
the short one is a"C" with lock washer.

[Rich P.]

Re: 63 and 64-67 Starter Bolts

David, great detailed post and information :-)
Here's what I've seen over the years and I'll see if I can get some pictures later tonight or this weekend have some Originals.
63 short bolt used a solid thick flat washer close 3/16 in thick.
The long bolt for 63 had a very unique head marking. It was C grade 8 but the lines were spread out in a Sunray effect instead of the Spades that we normally see in 64 on up.

The M grade 5 bolts that you have pictured, in my experience have come off of Pontiac starters. The way I know this is I did several huge buyouts of Pontiac restoration shops and those were the starter bolts that came in the barrels of buckets I purchased.

The three most common head markings on 64 up where C, RBW and O

[David L.]

Re: 63 and 64-67 Starter Bolts

Rich,

Thanks for the info.
My 1971 Pontiac Parts Catalog lists the 3830134 long bolt for All 1964-1970 models and the 3880880 short bolt for All 1964-1970 models w/250 eng. These are grade 8 bolts but maybe the 1964 bolts were a different part number and grade 5............The research continues.

Dave

[Alan D.]

Re: 63 and 64-67 Starter Bolts

The 64 AIM sec 6 sheet B1.00? (my AIM does not show sheet #, missing in copy)
#7 long bolt 3830134 both torque at 30-40 lb ft
#8 short bolt 3849418 has note of NPC-8

ref back to post 1
64-67 long bolt: GM # 3830134, 3/8"-16 X 4 21/32"
64-E65 short bolt: GM # 3849418, 3/8"-16 X 1 27/32"

[David L.]

Re: 63 and 64-67 Starter Bolts

Alan,
I sent you a PM.
Dave

[Alan D.]

Re: 63 and 64-67 Starter Bolts

And I sent one a while back and just another one, Saturday. Can not find if these are going through, used to work.
Well send directly to me at akayconsultants@yahoo.com Alan

[Timothy B.]

Re: 63 and 64-67 Starter Bolts

Dave,

I think you made a typo in the 1963 short bolt where you stated the length as 1 5/16" but should read 1 15/16" in length.

[David L.]

Re: 63 and 64-67 Starter Bolts

Dave,

I think you made a typo in the 1963 short bolt where you stated the length as 1 5/16" but should read 1 15/16" in length.

It was NOT my typo. My 1963 Chevrolet Parts Catalog (Oct. 1962) lists starter bolt # 3795470 as 3/8-15 X 1 5/16 as shown in the photo below.
It was a typo in the 1963 parts catalog. I thought that the length seemed a bit too short.
It should be 1 15/16" or 1.938"
The 3849418 and the 3880880 bolts are 1 27/32" or 1.844"
I guess that is why the 1963 used the special washer 3/32" thick or 0.094".
1.938" - 0.094" = 1.844" net

Also, a correction to my original post:
GM # 3830135 DOES appear in the 1963 AIM. GM # 3795470 was replaced by GM # 3830135 on 8-15-62 in the revision box but who know when it took place on the assembly line.

Thanks for your help in solving the bolt length error in the 63 parts catalog. Things now make sense.
Dave

[Joe L.]

Re: 63 and 64-67 Starter Bolts

Dave------


Parenthetical information in the part description column of the P&A catalogs is often subject to inaccuracy.

[Timothy B.]

Re: 63 and 64-67 Starter Bolts

Dave,

I went out and removed the starter bolts on my 63 coupe today to measure and try to add to your post. I have no idea if they are original to the engine, the 7242 starter was gone but these bolts must have came with the engine parts.

The long bolt is approx just a hair short of 4 3/4" long and has a slightly tapered end, it is flange head O marking and grade five, (three lines).

The short bolt measures approx 1 15/16, has a slight tapered end but not as much as the long bolt. It is a standard hex head (no flange) with a C marking and grade five, (three lines).

Both bolts have the (approx 1/2") upset shoulder just before the threads, typical of a starter bolt.

I didn't think mine were grade eight and I can't help but wonder when the grade eight bolts started being used and if that was why the part number changed.

I am pretty confident the bolts on my 67 300hp car are original and I'm thinking grade eight (not sure about flange head) but it's tight in a corner at present so i can't get a look.

One other thing I noticed and want to mention because we were talking about the sp. washer that's 3/32" thick used with the 1 15/16" short bolt on 1963 engines. The aluminum starter nose where the short bolt hole is located is not flat, it has a round machining approx 1/16" deep and the countersunk machining OD is slightly larger than that sp. washer. That sp. washer will index nicely in that countersink hole but I realize the order of assembly according to the AIM has the negative battery terminal then black ground wire then washer and bolt so the batt terminal would get squeezed into that machined area. I wonder if all those aluminum starter noses were like that at the short bolt hole or if that's where the sp. washer was ment to sit and the bolt head up against the harness ground wire.

[Alan D.]

Re: 63 and 64-67 Starter Bolts

The 63 Sp Washer, 3765135, spec is 13/32 X 11/16 X 3/32 It's not used (according to AIM)in 64

[Joe L.]

Re: 63 and 64-67 Starter Bolts

Here's some more starter bolt info:

The starter bolt used for all 1966-81 Corvettes with cast iron starter drive housing was GM #3733289. This bolt was 3-5/8" and of material grade GM-280M (SAE grade 5). Two of these bolts were used for each installation. The same bolt was used over the entire 1966-81 for these applications with cast iron starter drive housing and was available in SERVICE for many years thereafter. It is now GM-discontinued. The bolts pictured below are later SERVICE examples but are identical to the originals except for manufacturer's code:



The starter drive housing bolts used from 1966 to 1972 applications using aluminum housings with "1 long and 1 short" were as follows:

GM #3880880----1-27/32" length (also SERVICE for 1963-65)
GM #3830134----4-21/32" length (also used in PRODUCTION for L1963-65)

GM #3880880 was discontinued in November, 1971 and replaced by GM #1366042. The latter was replaced by GM #14087098 and, later GM #14097279 which remains available to this day. Below are photos of a GM #14097279:



The GM #3830134 was discontinued from SERVICE in December, 1971 and replaced by GM #1366043. GM #1366043 was discontinued in 1983 and replaced by GM #14057099 which was discontinued in 1994 and replaced by GM #14097278 which remains available to this very day. A GM #14097278 is shown below:



From 1970 through 1982 starter drive housings used for all applications with THM transmissions had an aluminum housing which utilized 2 long starter bolts. These bolts were the same as the long bolt used for the above-referenced "1 long and 1 short" aluminum drive housings and followed the same history as that described above.

For 1982, although the starter drive housing was the same basic configuration as the 1970-81 with THM, different starter bolts were used. These were the same size as the 70-81 bolts but they were of a special locking thread design. I do not see any reason that these bolts could not be used for 1970-81 applications or, even, the long bolt for 1963-72 applications using the "1 long and 1 short" aluminum housing. The original bolt used for 1982 was GM #14037730 but this was replaced for SERVICE by GM #12337924. Below find photos of the GM #12337924. Note the the unusual head design on the face of the head at the perimeter. This design denotes the locking thread:

[Timothy B.]

Re: 63 and 64-67 Starter Bolts

Joe,

Thanks for taking time and posting this starter bolt information plus the other posts regarding the different aluminum and cast iron starter housings.

[David L.]

Re: 63 and 64-67 Starter Bolts

Several years ago I bought starter bolt # 14057099 at my local Chevrolet dealer. The grade 5 bolt has "ABC" on the head, appears to be galvanized, and has a pointed end. The length measures 4 11/16" to the point but 4 9/16" to the end of the threads.