Did the 69 L71 come with the stainless locks

[george culolias]

Joe last question. No washers on bolts?

So the manifold bolts to the head with no other hardware besides the special bolts? The bolts dig into the manifold?

[george culolias]

Joe last question. No washers on bolts?

So the manifold bolts to the head with no other hardware besides the special bolts? The bolts dig into the manifold?

[Joe L.]

Re: Joe last question. No washers on bolts?

George-----

The special bolts, used only at the end runner positions, are a flanged head bolt. Flanged head bolts in general, and these bolts in particular, use no washer of any kind.

[Joe L.]

Re: Joe last question. No washers on bolts?

George-----

The special bolts, used only at the end runner positions, are a flanged head bolt. Flanged head bolts in general, and these bolts in particular, use no washer of any kind.

[george culolias]

Yikes so the bolts are different on the end runner

The bolts I got from CC are all the same. Are you saying 4 of the eight bolts per side are different? The special bolts. The other four that go to the inside runners, do they have washers? Do all the bolts look the same? Mine do. they are black and look alike. Okay and I lied, it wasn't the last question

[george culolias]

Yikes so the bolts are different on the end runner

The bolts I got from CC are all the same. Are you saying 4 of the eight bolts per side are different? The special bolts. The other four that go to the inside runners, do they have washers? Do all the bolts look the same? Mine do. they are black and look alike. Okay and I lied, it wasn't the last question

[Joe L.]

Re: Yikes so the bolts are different on the end ru

George-----

The bolts for the center runners are different. They are a standard, non-flanged hex head bolt. I don't think that any washers were used on these bolts. Under the assumption that a picture is worth a thousand words, I'm attaching a photo of both bolts. The flanged head bolt is used for the end positions (it's the locking style bolt) and the other is used for all other positions. The headmarking on these bolts may not be correct; otherwise the configuration of the bolts is correct.

[Joe L.]

Re: Yikes so the bolts are different on the end ru

George-----

The bolts for the center runners are different. They are a standard, non-flanged hex head bolt. I don't think that any washers were used on these bolts. Under the assumption that a picture is worth a thousand words, I'm attaching a photo of both bolts. The flanged head bolt is used for the end positions (it's the locking style bolt) and the other is used for all other positions. The headmarking on these bolts may not be correct; otherwise the configuration of the bolts is correct.

[george culolias]

You went out of your way for me, taking a pic!

Thanks. Corvette Central is not as smart as you! They only sent me the bolts on the left, not the locking bolts. Guess I'll have to look around for those. Thanks again Joe you are a lot of help!

[george culolias]

You went out of your way for me, taking a pic!

Thanks. Corvette Central is not as smart as you! They only sent me the bolts on the left, not the locking bolts. Guess I'll have to look around for those. Thanks again Joe you are a lot of help!

[Steve Antonucci]

Re: Yikes so the bolts are different on the end ru

Joe,

For what reason would the outer exhaust manifold bolts be different? Did this
hold true for all big blocks?

[Joe L.]

Re: Yikes so the bolts are different on the end ru

Steve------

Sometime in 1967, if not from the beginning of the model year, the outer position exhaust manifold bolts (actually, both bolts for all 4 end runner positions) were changed from retention by french locks to retention by special locking bolts.

The bolts for all other positions were a standard hex head bolt. These remained the same as earlier.

If you will note, the end runner bolt hole bosses are machined to a slightly lesser thickness than the bosses for the remaining bolts. This was originally done so that the same bolts could be used for all positions and the difference for the thickness of the french locks compensated for by the reduced thickness bosses. When the french locks were eliminated, the machining of the manifold bosses was not changed. Instead, since special bolts different from the other positions were going to be used, anyway, the length of these special bolts was slightly shortened from the other bolts. Thus, the special bolts are 1-3/16" long whereas the other bolts were 1-1/4" long.

These special bolts were used for all big blocks in passenger cars and light trucks through the 1975 model year, when big block use in passenger cars ended. Some folks think that all that happened was that french locks were eliminated for 1968 and that's it. That's NOT it. They were eliminated (as I mentioned, I believe during the 1967 model year, if not from the beginning of the model year) AND THEY WERE REPLACED BY THE UTILIZATION OF THE SPECIAL LOCKING BOLTS. The latter is the part that most folks have missed.

I have no doubt that many of these bolts "disappeared" over the years from engines on which they were originally installed. If they were removed for any reason, when re-installation took place the mechanic would likely think that the threads were "buggered up" since the bolts threaded-in with so much difficulty. Consequently, I would not be surprised if many were replaced for this reason. Locking style bolts, unlike lock nuts, are quite uncommon.

As far as I know, the locking style bolts were also used for engines with aluminum heads. So, I believe they were used for all 1968-69 L-89, L-88, and ZL-1 as well as 1971 LS-6. However, I don't like using these bolts on tappings in aluminum heads, with or without Heli-Coils. So, my "ZL-1" will not have them. I'll be using the 65-E67 style bolts with french locks. It won't be "correct", of course, but I'm not into nearly that level of correctness, at all, for this installation.