1968 Exhaust Manifold Question

[Mark Stocki]

Were french locks used on big block cars? From what I've read I don't believe so but I saw a vendor list them for sale. Can anyone confirm? Thanks.

[John C.]

Re: 1968 Exhaust Manifold Question

Mark

65 to 67 big blocks used french locks but 68 and later did not.

John

[Joe L.]

Re: 1968 Exhaust Manifold Question

Mark------

1968-74 big blocks used special locking bolts on the end runner positions for both sides (8 bolts total). These bolts had a flanged head with special threads. The remaining bolts were non-flanged, hex head bolts used with no washers.

I believe that some later 1967's also used the above-described.

[John H.]

Re: 1968 Exhaust Manifold Question

AMK Products (www.amkproducts.com) has those special locking BB exhaust manifold bolts; they also have the best automotive fastener catalog on the planet, bar none ($5.00, and worth it).

[Gerard F.]

Is this the bolt?

Joe,

Here is the bolt head:


This came off my 67 327/300 engine, when I had to remove the right side front bolt to add the Vintage Air compressor brace. Otherwise the exhaust manifolds and bolts have never been off my car in my 39 years with it.

Here's the exhaust manifold numbers:


Contrary to the Judging Guide this 06/26/67 S/B engine had no french locks:


The left side forward and aft sets of bolts look the same with no french locks.

Do I have an anomoly here?

It was nice lobstering with you, you know the good places.

Jerry Fuccillo
#42179

[Joe L.]

Re: Is this the bolt?

Jerry------

It's definitely not the same bolt used for big blocks. The big block bolt is shorter and the flanged head is configured differently. However, it's possible that this is a locking style bolt. It's easy to tell. If, even with clean threads, it threads in with difficulty, requiring the use of a wrench to turn it all the way, then it's probably a locking style bolt. If it threads in easily by hand, then it's not a locking style bolt.

By the way, my favorite lobster place has "been discovered". I've gone by there 3 times in the last week and 2 of those times there was so many cars parked there I didn't even bother to stop. The 3rd time, we had just eaten dinner somewhere else and just happened to drive by. That time, we could have gotten in.