70-72 bolt heads --anyone with a chart of what they have

[Mike E.]

Anyone who disassembled, either fully or partly, who documented bolt head patterns, and whether or not the bolt is cad or black oxide? If so, would you mind sharing what you found?
Thanks,
Mike Ernst

[Sheldon S.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Mike,
I am just finishing the chassis of my 71 BB car and I have spent countless hours finding correct bolts that had been replaced with incorrect ones and asking lots of questions on here. It would be easy for me to go and look at any bolts and tell you what I have done. Let me know which ones you need info on.
Sheldon

[Kevin G.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Anyone who disassembled, either fully or partly, who documented bolt head patterns, and whether or not the bolt is cad or black oxide? If so, would you mind sharing what you found?
Thanks,
Mike Ernst

Hello Rev.,

For the person that's up to the daunting task, an additional publication for the NCRS to sell would be "Fit and Finish Guide". One for each class, with notations made concerning running changes during each model year. It would be a lot of data to organize, but it would get tons of interest, I'd bet!

[Keith L.]

Re: 70-72 bolt heads --anyone with a chart of what they have

I'll take 2 for 70 please.

[Paul O.]

Re: 70-72 bolt heads --anyone with a chart of what they have

The problem that would occur is that the car someone disassembled and document the bolts and nuts would only help people who's cars were close to that production point. As Kevin pointed out there were running changes and workers could use bolts, nuts and washer that would meet the requirements of that item.
So you could have hundreds of changes in one year alone the task would be daunting to say the least.
I helped one of my chapter members here in Cincinnati restore his 71 LT-1 Early January build. When we would compare my 71 LT-1 Early September build there was on the frame alone 20 to 25 different finishes and head markings between the 2 cars. So you can see how difficult it would be to write a detailed reference book to cover all the changes.
During the past few year we have had the opportunity to view numerous Bowtie sharks. Just for an example the rear bumper bolts that attach the supports to the frame. On some cars the bolts are a mix of black and silver finish and the next car the mix is reversed then one car has all "M" bolts and the next has "A" bolts and the next is a mix of head markings.
It just would be very difficult just my 2 cents.

Paul 18046

[Rich P.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Mike,

the best you could ask for would be a physical description of the bolt for each application, known headmarkings and finish. 70-72 had a lot of new manufactures enter the mix (some were used in earlier years but only on a limited basis. As an example C/H in the middle started showing up on many applications as did O and [], BTS was used much more extensivly in 70-up cars also. Next you are also getting into the years that the way of finishing off the ends of the threads on self aligning bolts started to change, like sway bar cup retaining bolts and hood hinge bolts what they did was to move away from the "Pinched" end that formed a unthreded point to threads all the way to the pointed end. I can post pictures of these differences if you would like.
Over the past several years in addition to restoring cars I have been traveling all over the country to purchace 50's-60's to70's era GM bolts. Last month and yesterday I stopped at 2 old corvette salvage yards to start buying them out of thier hardware. In those 2 trips I have brought home 7-8 thousand pounds of hardware. I can post every concivable headmarking used for each application. In addition to that I have been frotunate enough to work on many unmlested cars since the very early 80's. I have always paid very close attention to the headmarkings and styls of bolts used in different application.

So if you have a particular request for a certin application I can post several different known headmarkings used for it. Just let me know. or e-mail me at annmariep@dejazzd.com. I'd be happy to help out a Man of the cloth

Thanks, Rich

[Mike G.]

Re: 70-72 bolt heads --anyone with a chart of what they have

probably no two just alike. the later the year model the better it was but i have seen several different configurations.

[Dick W.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Reverend Mike, I would think that they are black oxide, at least I have never seen any other color. But I never say never

[Mike E.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Thanks, guys. I have a 72 that's very original except the 2nd owner brightened it up with Dorman bolts everywhere. I have a bunch of original hardware from early C-3's--but acquired the hardware already off the cars.
I guess I'll use my 30k mile 71 LT-1 convert as the basis--the 72 is a reasonably early car.
Thanks for your responses.
Mike

[Patrick H.]

Re: 70-72 bolt heads --anyone with a chart of what they have

Mike,

I have an October 71 car and a June 72 car here, so if you need specifics let me know.

Patrick