S/B Exhaust Manifold French Locks

[Roger D.]

Purchased a set of French locks for the exhaust manifolds and they are shiny silver. Should they be blackened before I make the one bend over the bolt. I assume the bend is the front outside tab of each bolt, or does it matter. Well I read Joe L. French lock info so the early 69 S/B does not use French locks but a GM bolt # 3909821. Can you stil get these bolts and where might one find them. Thank YouRoger

[Joe L.]

Re: S/B Exhaust Manifold French Locks

Purchased a set of French locks for the exhaust manifolds and they are shiny silver. Should they be blackened before I make the one bend over the bolt. I assume the bend is the front outside tab of each bolt, or does it matter. Well I read Joe L. French lock info so the early 69 S/B does not use French locks but a GM bolt # 3909821. Can you stil get these bolts and where might one find them. Thank YouRoger

Roger-------


If I ever said what you said I said, then I must have been having delusions. ALL 1969 small blocks were equipped with french locks on the end exhaust manifold bolts. The GM #3909821 locking bolt was used only for BIG BLOCKS.

The french locks don't need to be "blackened". Natural steel is what they were. Of course, they will rust quickly. That's why I use stainless steel locks, albeit incorrect.

[Alan S.]

Re: S/B Exhaust Manifold French Locks

Hi Joe,
Speaking of french locks…. the 'tabs' on the locks from my 71 base sb are round, while the locks available now have square tabs.
Were locks with round 'tabs' typically used when the manifolds were installed in St.Louis, or might there have been square 'tabs' too?
Regards,
Alan

[Roger D.]

Re: S/B Exhaust Manifold French Locks

Roger-------If I ever said what you said I said, then I must have been having delusions. ALL 1969 small blocks were equipped with french locks on the end exhaust manifold bolts. The GM #3909821 locking bolt was used only for BIG BLOCKS.The french locks don't need to be "blackened". Natural steel is what they were. Of course, they will rust quickly. That's why I use stainless steel locks, albeit incorrect.

Thanks Joe, I notice that as I get older I am screwing up allot of things that I am reading. My bad. ThanksRoger

[Roger D.]

Re: S/B Exhaust Manifold French Locks

Purchased a set of French locks for the exhaust manifolds and they are shiny silver. Should they be blackened before I make the one bend over the bolt. I assume the bend is the front outside tab of each bolt, or does it matter. Well I read Joe L. French lock info so the early 69 S/B does not use French locks but a GM bolt # 3909821. Can you stil get these bolts and where might one find them. Thank YouRoger

Please correct me if I am wrong but I did not think the 1969 base model 350/300 had French locks on the rear flange of the half shafts. I f so I will need to get them, OOPs!!

[John H.]

Re: S/B Exhaust Manifold French Locks

Were locks with round 'tabs' typically used when the manifolds were installed in St.Louis, or might there have been square 'tabs' too?
Regards,
Alan

Alan -

The small-block exhaust manifolds were installed at the Flint V-8 Engine Plant. but the bolts were removed/re-installed at St. Louis to install the horizontal ignition shielding brackets.

[Joe L.]

Re: S/B Exhaust Manifold French Locks

Please correct me if I am wrong but I did not think the 1969 base model 350/300 had French locks on the rear flange of the half shafts. I f so I will need to get them, OOPs!!

Roger-----


French locks were used on the half shaft flanges for ALL 1969 Corvette applications (as well as all other 1964-82 Corvette applications).

[Christopher K.]

Re: S/B Exhaust Manifold French Locks

Hi Joe,
Speaking of french locks…. the 'tabs' on the locks from my 71 base sb are round, while the locks available now have square tabs.
Were locks with round 'tabs' typically used when the manifolds were installed in St.Louis, or might there have been square 'tabs' too?
Regards,
Alan

Alan

Great question - I was wondering about the same thing. Mine are round on my '72 sb also.

[Alan S.]

[Roger D.]

Re: S/B Exhaust Manifold French Locks

Thanks Joe, I will get a set tomorrow.

[Peter S.]

Re: S/B Exhaust Manifold French Locks

Hey Roger,

Here is a french lock off of my '69. I believe these were replaced in 1971 as part of my Chevrolet Engine replacement, so I cannot fully confirm for you the configuration of the "ears" in respect to 1969. My manifolds are dated correctly and were attached to dated correct heads, and I had to drill out two of the exhaust manifold bolts. This is my sole basis to believe that they have not been replaced since 1971. But, maybe it will help clarify the roundness of them?

Maybe it will help clarify the bend?
DSC_8764.jpg

DSC_8762.jpg

[Roger D.]

Re: S/B Exhaust Manifold French Locks

Thanks for the pictures Peter, they help me a lot. I think Paragon and Zip have the rounded locks so I will go to them first. Thank youRoger