1971 LT-1 Intake Bolt Markings/Color

[Paul C.]

Noticed that there were several different bolts (different head markings) on my 71 LT-1. Trying to figure out for judging what is correct. Here are the head markings for my intake bolts starting with the drivers side front. All bolts have 3 lines 120 degrees apart.

1. Motor lifting bracket (2 bolts): A with a shoulder and orange.
2. C and aluminum color (AL)
3, CBS & AL
4. C & AL
5. C & unpainted--ignition shield bracket Left

Passenger side front
1. Air Pump bolt in intake: M & orange
2.,3.,4.,: C & AL
5. SB & AL--ignition shield bracket Right
6. C & AL

All bolts have a washer except the ones on the motor liftin bracket and the AIR pump.

I assume they should all be Aluminum color and have a "C" on them with the exception of the motor lifting bracket bolts (A) and the AIR pump (M)hich should be orange.

I hope this doesn't sound to confusing. I want to make sure they are correct before having the car judged.

Thanks Paul

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Noticed that there were several different bolts (different head markings) on my 71 LT-1. Trying to figure out for judging what is correct. Here are the head markings for my intake bolts starting with the drivers side front. All bolts have 3 lines 120 degrees apart.

1. Motor lifting bracket (2 bolts): A with a shoulder and orange.
2. C and aluminum color (AL)
3, CBS & AL
4. C & AL
5. C & unpainted--ignition shield bracket Left

Passenger side front
1. Air Pump bolt in intake: M & orange
2.,3.,4.,: C & AL
5. SB & AL--ignition shield bracket Right
6. C & AL

All bolts have a washer except the ones on the motor liftin bracket and the AIR pump.

I assume they should all be Aluminum color and have a "C" on them with the exception of the motor lifting bracket bolts (A) and the AIR pump (M)hich should be orange.

I hope this doesn't sound to confusing. I want to make sure they are correct before having the car judged.

Thanks Paul

Paul,

My 1970 LT1 has something like 7 different head mark/configuration intake bolts -- I forget the exact number, but I have posted about this in the distant past. When I see an intake (regardless of engine type) with all the head marks the same I know the fasteners came from a kit from the Corvette big-box resto stores. Flint and Tonawanda didn't care one twit about head marks other than the three lines you noted -- which indicate grade 5 fasteners. And actually only the fastener engineer(s) cared about that. The guys stocking the engine assembly line IDed the fasteners by part number, and the assembler grabbed the fasteners from the appropriate supply location.

Sounds to me like there is a good chance you have the original fasteners. Oh, and FWIW mine were painted silver with the intake. As the paint has come off because of the persistent Holley fuel leaks I note most of the fasteners are black.

[Paul C.]

Re: 1971 LT-1 Intake Bolt Markings/Color

How about the judging team. Will they deduct points because they have different markings? Do yours have washers? I don't care about the markings either--I agree with you but do the judges agree with us. I will leave them as they are regardless of NCRS. Thanks for the input. I will make sure the color is OK (3 orange ones) and ignore the markings.
Paul

[Patrick H.]

Re: 1971 LT-1 Intake Bolt Markings/Color

How about the judging team. Will they deduct points because they have different markings? Do yours have washers? I don't care about the markings either--I agree with you but do the judges agree with us. I will leave them as they are regardless of NCRS. Thanks for the input. I will make sure the color is OK (3 orange ones) and ignore the markings.
Paul

Terry has been on the "Judging Team" as long as 70-72s have been judged. You can pretty much take his word for it on these bolts. Read his post again regarding the bolt head markings.

[Paul C.]

Re: 1971 LT-1 Intake Bolt Markings/Color

I won't worry about the markings but can some clarify the color of the bolts. The front engine bracket is orange but it (judging manual) doesn't specify color bolts but the color of the rear lifting bracket bolt is natural. The AIR one is supposed to be orange to match the bracket?? Are all the rest aluminum?

THANK YOU!!!!!!!!!!!!!!!!!!!For your Help.

Paul

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Terry has been on the "Judging Team" as long as 70-72s have been judged. You can pretty much take his word for it on these bolts. Read his post again regarding the bolt head markings.

OK grass hopper --

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

I won't worry about the markings but can some clarify the color of the bolts. The front engine bracket is orange but it (judging manual) doesn't specify color bolts but the color of the rear lifting bracket bolt is natural. The AIR one is supposed to be orange to match the bracket?? Are all the rest aluminum?

THANK YOU!!!!!!!!!!!!!!!!!!!For your Help.

Paul

[Robert S.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Paul,
Regarding your question on the use of washers under the intake manifold bolts, I am almost sure they were not used for your application. However, the more knowlegeable members may confirm.

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Paul,
Regarding your question on the use of washers under the intake manifold bolts, I am almost sure they were not used for your application. However, the more knowlegeable members may confirm.

We are talking LT1s now: No washers on 1970, maybe on very late 1971 -- yes, washers for 1972(actually I believe they are built into the bolts, but I will leave that to those who have had a 1972 apart). I know Sal knows, but I am sure there are others.

[Paul C.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Still trying to figure out the markings on the 12 bolts on the 1971 LT-1 intake manifold. Terry or Sal??

Thank you Paul

[Paul C.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Paragon: 10 bolts 3/8-16 x 1 1/8 with M marking (black phosphtae) & 2 bolts 3/8-16 x 1 1/8 TR marking (chrome color)

Ecklers: 10 bolts 3/8-16 x 1/1/8 with M marking & 2 bolts 3/8-16 x 1 1/8 with double circle marking---all bolts black phosphate

?????????

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Paragon: 10 bolts 3/8-16 x 1 1/8 with M marking (black phosphtae) & 2 bolts 3/8-16 x 1 1/8 TR marking (chrome color)

Ecklers: 10 bolts 3/8-16 x 1/1/8 with M marking & 2 bolts 3/8-16 x 1 1/8 with double circle marking---all bolts black phosphate

?????????

And that is exactly why you will receive a deduction (perhaps 1 point) for all the bolts having the same headmark. That is what I told you some years ago, and nothign has changed since then, except I have more gray hair.

[Paul C.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Just saw a post on another forum by a fellow 71 LT-1 owner and he said 10 bolts have an M on them and the 2 for the engine lift bracket have a double circle. No washers on any of them. Mine are wrong because they have washers of them. That would agree with the Ecklers description.

[Terry M.]

Re: 1971 LT-1 Intake Bolt Markings/Color

Just saw a post on another forum by a fellow 71 LT-1 owner and he said 10 bolts have an M on them and the 2 for the engine lift bracket have a double circle. No washers on any of them. Mine are wrong because they have washers of them. That would agree with the Ecklers description.

That sounds to me like his have been replaced. I have yet to see original bolts with all 10 having the same headmark, but I suppose it could happen. It is kind of like the famous lawyer question: "Is it possible?"