Who had the pictures of the "HD" rear spindles?

[Bob J.]

Re: Who had the pictures of the "HD" rear spindles?

Bob -- re '63-4's: here's 2 pics I have off a Jan '64 car (not on the road since '68). I see what looks like a (partial) stamped "2" on one, and a "3" on the other. Might have been a rebuilder adder.

Also, also a pic of a '65-up that shows the two circular marks that the OP and others are discussing.

General request: on the 2nd pic, I can't get the drum off as the shoes are frozen to it. Any suggestions ?

Hi Wayne, I have a spindle stamped 3 exactly like yours.
No idea what it means but I don't think its from a rebuilder. Bob

[Jim T.]

Re: Who had the pictures of the "HD" rear spindles?

I think I am the guy you are looking for. Attached is a picture of the original spindle of an 38,000 mile 1970 LT-1 that I have owned since 1972. The rotor is still riveted on. Please excuse the 1976 aluminum wheels. The indented mark on the left ear I think signifies the heavy duty spindle for LT-1s and big blocks in 1970. Hopefully other owners of 70's with original spindles will offer more photos.

The Corvette section of the 1970 Chevrolet Sales Album has a chart on page 10 for "Equipment included with Optional V8 Engines." It lists "heavier duty rear wheel spindle support arms" as included with LT-1, LS-5 and LS-7, but not with L-46. I opined that this information matched my observation that orginal LT-1s had the holes in the trailing arms for rear sway bars, like big blocks, even though LT-1s did not have rear sway bars because they used the same big block trailing arm assembly. The parts books list spindles, supports and torque arms but not "spindle support arms", so I think this terms must refer to the assembly. I don't think there is anything heavy duty about the arm or the support on big blocks which leaves only the spindle as a possible heavy duty part. I have seen twisted spindles so I see the purpose for a HD part.

I don't know if my 67 L-71 still has its original spindles. They d[ATTACH=CONFIG]49220[/ATTACH]o not have the same distinctive mark as the LT-1 spindle.

Patrick my original owner 1970 350/300 with turbo 400 and original trailing arms that have the holes in the trailing arms for rear sway bar. I even even installed a rear sway bar with original type brackets for a few years of driving but have removed it.

[Patrick B.]

Re: Who had the pictures of the "HD" rear spindles?

Jim, if it has the sway bar holes, it may well have the HD spindles also. Send us a picture of spindle end. Does it also have the big block style rear end with caps instead of u-bolts on the half-shaft flanges?

[John H.]

Re: Who had the pictures of the "HD" rear spindles?

Don't know about C3's, but in '67, which also had the brutal L-71/L-89/L-88 engines, there was only one part number rear trailing arm assembly, used on everything from the base Powerglide to the L-88 (with holes drilled at St. Louis for the big-block rear stabilizer bar attachment). If there was a "heavy-duty" rear spindle, it would have created a unique part number for that trailing arm assembly, and that didn't happen. I don't see anything that documents the existence of a "heavy-duty spindle".

[Steven B.]

Re: Who had the pictures of the "HD" rear spindles?

BFH and Kroil

Exactly! Like Dick said. I had the same problem a couple of months ago with a YJ-8 on my '78 and also a steel wheel on my '77. I sprayed around spindle, lug nuts, and from back between hub and wheel over a two day period and really soaked it all the time whacking with a 2 pound sledge then went to a 5 pound. They came off but it was frustrating. Steve

[Dick W.]

Re: Who had the pictures of the "HD" rear spindles?

Don't know about C3's, but in '67, which also had the brutal L-71/L-89/L-88 engines, there was only one part number rear trailing arm assembly, used on everything from the base Powerglide to the L-88 (with holes drilled at St. Louis for the big-block rear stabilizer bar attachment). If there was a "heavy-duty" rear spindle, it would have created a unique part number for that trailing arm assembly, and that didn't happen. I don't see anything that documents the existence of a "heavy-duty spindle".

Your post made me go look. I have the "HD" parts section from several parts books prior to the publication of the Sport Equipment book which morphed into the Chevrolet Power book. NONE of those pages or books reference a special rear spindle for a Corvette. There is a lot of competition preparation info there that references many special pieces.

[Gary R.]

Re: Who had the pictures of the "HD" rear spindles?

Well I guess that pretty much settles the GM rear HD spindle question. When I build a HP IRS I use Tom's HD spindles. For those that are not familiar with what they look like here is a stock spindle on the left and Tom' 31's on the Right.

If you want to see more of them I can dig through my files. Otherwise I have my answer to my original question.

[Patrick B.]

Re: Who had the pictures of the "HD" rear spindles?

Don't know about C3's, but in '67, which also had the brutal L-71/L-89/L-88 engines, there was only one part number rear trailing arm assembly, used on everything from the base Powerglide to the L-88 (with holes drilled at St. Louis for the big-block rear stabilizer bar attachment). If there was a "heavy-duty" rear spindle, it would have created a unique part number for that trailing arm assembly, and that didn't happen. I don't see anything that documents the existence of a "heavy-duty spindle".

The 1970 assembly manual does show different part numbers for the trailing arm assemblies in UPC 4 sheet A2 and under the big block option UPC LS5 sheet B2 with the note that the big block part number was added 7-7-69.

[Joe L.]

Re: Who had the pictures of the "HD" rear spindles?

The Chevrolet Power Manual states regarding Corvette chassis set-up for racing purposes:

"... use rear spindle part number 3872476 which is a high nickel alloy forging and has proven satisfactory..."

The 3872476 is the only SERVICE spindle which has ever been cataloged for 1965-82 Corvettes. As I mentioned previously, IF there ever was a special "heavy duty" spindle, then the 3872476 must be it and the Power Manual reference pretty much confirms that.

I have observed a small, stamped, diamond on one of the nubs on the center of 3872476 spindles. However, I have no reason to believe this has anything to do with a "heavy duty" designation. The markings seen on other spindles as have been reported by others previously in this thread could mean a whole lot of things and have absolutely nothing to do with a "heavy duty" designation.

[Joe L.]

Re: Who had the pictures of the "HD" rear spindles?

Well I guess that pretty much settles the GM rear HD spindle question. When I build a HP IRS I use Tom's HD spindles. For those that are not familiar with what they look like here is a stock spindle on the left and Tom' 31's on the Right.

If you want to see more of them I can dig through my files. Otherwise I have my answer to my original question.

Gary------


The Tom's spindle looks very stout. Obviously, it would require, at a minimum, a different spindle flange than stock. However, can it be used with a stock, unmodified bearing support and can the spindle flange required be used with stock half shafts and stock half shaft flanges?

[Patrick B.]

Re: Who had the pictures of the "HD" rear spindles?

I just got a 1970 assembly manual recently, and I looked at it for the first time today. The standard "Spindle Sup Arm & Brake Asm." is listed as 3936647-8. Under the LS-5 option, the "Spindle Sup Arm & Brake Asm." is listed as 3936649-70.
I hope some people with non-LT-1 small block cars with 4 speeds send in spindle photos so we can see if the spindle was the reason for the part number difference.

[Gary R.]

Re: Who had the pictures of the "HD" rear spindles?

Hi Joe, Yes the stock supports are reused and not modified in any way. The bearing cones are the same inner and outer but a different and much more expensive inner race is used. The spindle flanges are huge compared to the stock ones. An inner steel bushing is part of the axle kit to use a different size inner seal. The 1/2 shafts used typically in this application are Toms 3.5" 1350 shafts but stock shaft will bolt up to the 1350 setup. There is also a 1480 axle kit that is a combination 12 bolt diff conversion and outer spindle build. These require modification to the arm bump stop and only Tom's 1480 1/2 shafts. This is for extreme use, my son has a 1350 setup I built him but I think we will have to step up to the 1480 setup to hold things together at the track. This shows the axles and flanges I used in a previous build.

[Joe L.]

Re: Who had the pictures of the "HD" rear spindles?

Gary------


It's a very nice set-up without a huge divergence from stock configuration, especially in the 1350 version. The fact that this set-up is wise in high performance applications highlights the inherent weakness of the stock Corvette IRS system. I've been saying this for years. Very often I hear of folks wanting to greatly upgrade the horsepower and torque of Corvette engines. Well, like I've said before, unless one is also willing to upgrade the IRS system (including differential), adding more power is asking for trouble. The stock Corvette system is marginal at best. There IS such a thing as too much power in a Corvette (with stock IRS system)!

[Joe L.]

Re: Who had the pictures of the "HD" rear spindles?

I just got a 1970 assembly manual recently, and I looked at it for the first time today. The standard "Spindle Sup Arm & Brake Asm." is listed as 3936647-8. Under the LS-5 option, the "Spindle Sup Arm & Brake Asm." is listed as 3936649-70.
I hope some people with non-LT-1 small block cars with 4 speeds send in spindle photos so we can see if the spindle was the reason for the part number difference.

Patrick------

The first two photos, below, are the known original spindles from my September, 1969 build, original owner 1969 Corvette with 300/350. The second two photos are from a pair of SERVICE GM #3872476 spindles that I purchased in about 1980. The photos that I will post in the next post (because of photo posting limits) are from a pair of GM #3872476 spindles I purchased in about 1996.


DSCN2922.jpgDSCN2923.jpgDSCN2924.jpgDSCN2924.jpg

[Joe L.]

Re: Who had the pictures of the "HD" rear spindles?

The following are photos of the 3872476 spindles I purchased about 1996:


DSCN2927.jpgDSCN2926.jpg


I also did some further research on the spindles and I found that there was another part number once used for the spindles but it had nothing to do with "heavy duty" or "non-heavy duty". It seems that ALL 1965 and early 1966 Corvettes used spindles GM #3865904. Later 1966 and all later Corvettes used GM #3872476 which also replaced the 3865904 for SERVICE in March, 1966. I do not know what the difference was between these spindles.