67 French Locks on Manifolds

[Tom D.]

Re: 67 French Locks on Manifolds

Kirk,

See page 6-27 of the Chevrolet Chassis Service manual for a description of removal and installation of exhaust manifold French locks. Also page 82 of the 67 TIM & JG describes the spacer washers. The bolts and washers are "plated black".

[Mike M.]

Re: 67 French Locks on Manifolds

Hi Joe,
Question about the length of this bolt.
2" ?????
Would this be typical GM?
Thank you,
HaND

[Kirk M.]

Re: 67 French Locks on Manifolds

Kirk,

See page 6-27 of the Chevrolet Chassis Service manual for a description of removal and installation of exhaust manifold French locks. Also page 82 of the 67 TIM & JG describes the spacer washers. The bolts and washers are "plated black".

So, if mine aren't plated black, should I paint them black before installing?

[Joe L.]

Re: 67 French Locks on Manifolds

Hi Joe,
Question about the length of this bolt.
2" ?????
Would this be typical GM?
Thank you,
HaND

Mike-----


It's longer than typical for the end bolt positions of small blocks. The typical small block original end bolts were about 1-1/2" long. These were standard hex head without flange and used with the french locks.

The big block, flanged head, locking bolt which was SUPPOSED to have been used for end positions from Late 1967-74 was 1-3/8" long.

So, the bolts that Jerry has are not the same IN LENGTH as the big block bolts. As far as I can find, the bolts that Jerry has were never SERVICED. If they were, I can't find a part number for them anywhere.

[Tom D.]

Re: 67 French Locks on Manifolds

Kirk,

I believe the term "plated black" her really means the black phospate type finish for bolts and washers. I bought black phosphate bolts and washers from corvette central because my bolts were worn out. I also found a product you can cook bare metal bolts or parts in to give them the black coating. (Zinc Parkerizing Solution from Mullikin"s 864-845-0838)

[Kirk M.]

Re: 67 French Locks on Manifolds

Are the French locks themselves suppose to be black plated, or does that refer to the washers and bolts holding them in place?

[Joe L.]

Re: 67 French Locks on Manifolds

Are the French locks themselves suppose to be black plated, or does that refer to the washers and bolts holding them in place?

Kirk----


The french locks are natural finish, carbon steel. They rust VERY rapidly.

[Michael H.]

Re: 67 French Locks on Manifolds

Sorry for my stupidity here, but I have not seen these installed before so I'm try to get it straight in my head. Do I have it correct:

1. Gasket
2. Manifold
3. On outer two manifold bolts
- washer
- French lock
- Bolt
4. Bend up tabs to prevent bolts from backing out

Is that correct? Does anyone have a picture? Thanks.

Kirk

Toss the gasket and only bend one tab per bolt. Not both. Bend the one that aligns with a flat on the hex bolt head.
It's not possible to have both tabs aligned with two flats on the bolt head.

The bolts, spacers and lock straps (if so equipped) were painted engine color on ALL V8 engines from the 1955 model through the end of the 65 model year and through at least the 67 model year on big blocks. (although late 67 big blocks may not have the straps, as mentioned by others)

[Dave E.]

Re: 67 French Locks on Manifolds

A very timely thread for me......fussing over my 67 small block mid june built car in prep for flight judging this coming Saturday. I have owned the car since 1971....never judged before....driven the first 20 years....stored the last 20.....retirement now allowing me time to reconnect with the car.

I was re installing the exhaust manifolds yesterday after cleaning and I was doing some research (aim,forum,judging guides, etc) to make sure that I would install the new repo french locks and thick washers that I had just purchased correctly.

I discovered that (8) of my exhaust manifold bolts are exactly as pictured by member 42179 Gerald Fin in this thread.

The shoulder (integral washer) on these bolts defeats the locking tab on the french lock.

Decision time......add the locks and washers as required by the guide even though they are useless with my manifold bolts??

I chose not to install the locks and thick washers.....maybe adios to a coupla points....but true to the car's actual build configuration in my opinion.

[Stephen L.]

Re: 67 French Locks on Manifolds

If you read the entire thread I believe you'll come to the conclusion that:

Small block engines had a change in the bolt style during 1967; early engines used a bolt with no intergral washer and used separate washers and locks: late engines used the bolt intergral with a washer and no locks or additional washer

The bolts with the intergral washer do NOT require additional washers and french locks.

French locks require that the washer must be installed ON THE BOLT (when the locks are required) AFTER the french lock placing the lock CLOSEST to the bolt head.

Post your approximate build date to aid in determining when the bolt change took place......

[Gerard F.]

Re: 67 French Locks on Manifolds

Dave,

You don't need no stinkin' french locks. My 67 327/300 is vin 22049, with a June 29, 1967 build date, the engine stamping is V0626HE.

The bolt I took off and pictured above was taken off for the first time. I have 7 other bolts the same on the exhaust manifold which have never been touched, and have NO French Locks.

[John H.]

Re: 67 French Locks on Manifolds

My #20401 (June 8th build), V0601HE, has regular bolts and french locks.

[Keith B.]

Re: 67 French Locks on Manifolds

I do not see the french lock debate come up often here.........while on the topic I looking for one french lock for my 66 TF BB car. I have three and am missing one. Looking to purchase (1) Steel French lock for my BB car.

I have searched in vain on e--ay, corvette forum, etc etc. As you know for juding I need a steel BB lock....thx

Pls PM me or e-mail me direct at khbramhill@telus.net