Big Block Leaf Spring

[Joe L.]

Re: Big Block Leaf Spring

Jerry-----

As others have mentioned, the rear sway bar was part of the big block option ONLY during the 65-74 period. During these years, if you ordered ANY big block, with or without F-41, you got the rear sway bar. If you ordered a small block, with or without F-40/41, you DID NOT get a rear sway bar. For the 65-74 period, the rear sway bar was NOT part of any suspension option. From 1975 onward, a rear sway bar WAS part of suspension option FE-7.

Also, about 15 years ago GM replaced, for SERVICE, the 9 leaf rear spring with the 7 leaf spring. So, if someone had replaced the rear spring in that general time frame and purchased a replacement spring from GM, they would have been sold the 7 leaf spring. That's one possibility of how the 7 leaf spring got on your car.

[Joe L.]

Re: Big Block Leaf Spring

Jerry-----

As others have mentioned, the rear sway bar was part of the big block option ONLY during the 65-74 period. During these years, if you ordered ANY big block, with or without F-41, you got the rear sway bar. If you ordered a small block, with or without F-40/41, you DID NOT get a rear sway bar. For the 65-74 period, the rear sway bar was NOT part of any suspension option. From 1975 onward, a rear sway bar WAS part of suspension option FE-7.

Also, about 15 years ago GM replaced, for SERVICE, the 9 leaf rear spring with the 7 leaf spring. So, if someone had replaced the rear spring in that general time frame and purchased a replacement spring from GM, they would have been sold the 7 leaf spring. That's one possibility of how the 7 leaf spring got on your car.

[Mike Cobine]

Re: Big Block Leaf Spring

Another possibility on how you got a 7 leaf is that almost everyone who gave it more than half throttle from every stop sign and light wanted more bite off the line. So you bought the HD 7 leaf spring from your local dealer, and 6 bolts later, it was in.

Less squat, more bite, faster take off.

Rember, from 1966 to the early '80s, the odds are the owner ran it and ran it hard more than once. And probably did things to make it run harder.

Until everyone began restoring as an investment in the '80s, these were just hot rods and were often modified.

[Mike Cobine]

Re: Big Block Leaf Spring

Another possibility on how you got a 7 leaf is that almost everyone who gave it more than half throttle from every stop sign and light wanted more bite off the line. So you bought the HD 7 leaf spring from your local dealer, and 6 bolts later, it was in.

Less squat, more bite, faster take off.

Rember, from 1966 to the early '80s, the odds are the owner ran it and ran it hard more than once. And probably did things to make it run harder.

Until everyone began restoring as an investment in the '80s, these were just hot rods and were often modified.

[Mike Cobine]

Standard only means "Not Optional"

There are many sets of front springs. The small block had some, the big block had its own, and I think the AC cars had a different set in some years. Then there were the F41 front springs.

However, only the F41 were optional. The others were all Standard based on the configuration of the car. You could not order the other Standard springs.

Likewise, the rear sway bar is Standard on all big blocks. It isn't an option you could add or subtract.

Standard does not mean Base.

Base means the car that comes without any options.

And to throw it all nuts, there were "required options", which some mistake as "Standard" for a configuration. Required options are like A01 Tinted Glass on C60 Air Conditioned cars.

J56 Brakes, K66 Transistor Ignition, M22 transmission, F41 suspension, and such are "required options" on the L88 engine "option". You couldn't have an L88 without those options (thus many think they are "standard") but they were not included in the price or the order, so they were options.

And there are "restricted options" which were only available when combined with other options, like F41 in 1966 on the 425 hp engine.

The fun has only begun. Step this way for Full Confusion 101.

[Mike Cobine]

Standard only means "Not Optional"

There are many sets of front springs. The small block had some, the big block had its own, and I think the AC cars had a different set in some years. Then there were the F41 front springs.

However, only the F41 were optional. The others were all Standard based on the configuration of the car. You could not order the other Standard springs.

Likewise, the rear sway bar is Standard on all big blocks. It isn't an option you could add or subtract.

Standard does not mean Base.

Base means the car that comes without any options.

And to throw it all nuts, there were "required options", which some mistake as "Standard" for a configuration. Required options are like A01 Tinted Glass on C60 Air Conditioned cars.

J56 Brakes, K66 Transistor Ignition, M22 transmission, F41 suspension, and such are "required options" on the L88 engine "option". You couldn't have an L88 without those options (thus many think they are "standard") but they were not included in the price or the order, so they were options.

And there are "restricted options" which were only available when combined with other options, like F41 in 1966 on the 425 hp engine.

The fun has only begun. Step this way for Full Confusion 101.

[Terry F.]

Re: Big Block Leaf Spring

Get this, I it is possible that your car came with a 7 leaf rear spring from the factory. Chevrolet wasn't perfect when it came to getting stuff out the door. Supose they ran out of 9 leaf type. You think that would stop the line? I don't think so. So....should it have left the factory with a 7 leaf? Probably not. But, that would not have stopped them from turning it out with one.

There are suttle differences between rear leaf springs throughout each year of production. If your spring looks original to the car and looks the same as the other high horse cars of that year, I would probably leave it.

I respect the opinions that have been given to you. These people really know this stuff. But, I am of the opinion that all sort of things happened on the line during production. Everyone feels differently about what a restoration means. If it were my car and I liked the way it drove, I would probably leave it. Have fun, Terry

[Terry F.]

Re: Big Block Leaf Spring

Get this, I it is possible that your car came with a 7 leaf rear spring from the factory. Chevrolet wasn't perfect when it came to getting stuff out the door. Supose they ran out of 9 leaf type. You think that would stop the line? I don't think so. So....should it have left the factory with a 7 leaf? Probably not. But, that would not have stopped them from turning it out with one.

There are suttle differences between rear leaf springs throughout each year of production. If your spring looks original to the car and looks the same as the other high horse cars of that year, I would probably leave it.

I respect the opinions that have been given to you. These people really know this stuff. But, I am of the opinion that all sort of things happened on the line during production. Everyone feels differently about what a restoration means. If it were my car and I liked the way it drove, I would probably leave it. Have fun, Terry

[Jerry M.]

Re: Big Block Leaf Spring

Gentlemen. I think I have it now. When the juding manual says 9 leaf springs are "standard" it means sort of standard and sort of not. There is a sort of standard for small blocks and a sort of standard for big blocks and then there is F 41 the "unstandard". When Noland Adams says he documented F 41 390's but it was only available on 425's exactly what "standard" does that fall under?
I think you are all right, but I tend to agree most with Joe that is probably a service replacement spring that still looks correct.
I appreciate the full response and think I will leave it on and take the originality hit as an SR spring. It is still in very good condition.
Thanks again!

[Jerry M.]

Re: Big Block Leaf Spring

Gentlemen. I think I have it now. When the juding manual says 9 leaf springs are "standard" it means sort of standard and sort of not. There is a sort of standard for small blocks and a sort of standard for big blocks and then there is F 41 the "unstandard". When Noland Adams says he documented F 41 390's but it was only available on 425's exactly what "standard" does that fall under?
I think you are all right, but I tend to agree most with Joe that is probably a service replacement spring that still looks correct.
I appreciate the full response and think I will leave it on and take the originality hit as an SR spring. It is still in very good condition.
Thanks again!

[Mike Cobine]

Re: Big Block Leaf Spring

But, I am of the opinion that all sort of things happened on the line during production.

Agreed. I grew up near St. Louis and had neighbors that worked there. They had lots of tales, especially once they found out how much I liked Corvettes.

How much of those tales were true, and how much fiction, I would never venture to say. But I know that in all manufacturing in that area, short cuts were made, lines were not shut down for something that could be substituted quickly, and as long as things worked, QC sometimes looked the other way.

I have no reason to believe a bunch of UAW workers doing their 8 hour shift on a car most of them couldn't afford would do any different.

Trips through the St. Louis Corvette plant at night revealed things that daytime engineers and supervisors never saw. And most things seen then just verified those workers worked like everyone else back then. They weren't master craftsmen who would stop the world to perfect a run in the paint on a part, just guys who punched a clock in and then out 8 hours later, who worried more about the Cards on Sunday, if traffic on 70 would make them a half hour late or an hour late for dinner, and if the boat would run well enough to go skiing that weekend than whether or not they put the right distributor in the hole or the wrong fill tube in the manifold or the wrong bolts on the chassis.

[Mike Cobine]

Re: Big Block Leaf Spring

But, I am of the opinion that all sort of things happened on the line during production.

Agreed. I grew up near St. Louis and had neighbors that worked there. They had lots of tales, especially once they found out how much I liked Corvettes.

How much of those tales were true, and how much fiction, I would never venture to say. But I know that in all manufacturing in that area, short cuts were made, lines were not shut down for something that could be substituted quickly, and as long as things worked, QC sometimes looked the other way.

I have no reason to believe a bunch of UAW workers doing their 8 hour shift on a car most of them couldn't afford would do any different.

Trips through the St. Louis Corvette plant at night revealed things that daytime engineers and supervisors never saw. And most things seen then just verified those workers worked like everyone else back then. They weren't master craftsmen who would stop the world to perfect a run in the paint on a part, just guys who punched a clock in and then out 8 hours later, who worried more about the Cards on Sunday, if traffic on 70 would make them a half hour late or an hour late for dinner, and if the boat would run well enough to go skiing that weekend than whether or not they put the right distributor in the hole or the wrong fill tube in the manifold or the wrong bolts on the chassis.

[Mike Cobine]

What are your goals?

That is the main thing to determine. If you want to have the car judged, then build it according to the judging guide and what those on here have told you is correct for the JG.

If your goal is to fix it up nice, then do what you want. Keep the spring if you like it, get rid of it if you think it too stiff or if you want it "correct".

[Mike Cobine]

What are your goals?

That is the main thing to determine. If you want to have the car judged, then build it according to the judging guide and what those on here have told you is correct for the JG.

If your goal is to fix it up nice, then do what you want. Keep the spring if you like it, get rid of it if you think it too stiff or if you want it "correct".

[Michael H.]

Re: Big Block Leaf Spring

It's HIGHLY unlikely that any cars rolled out of the St. Louis plant with standard springs in the front and F41's in the rear. When a car goes into production, the parts quantity needed to complete the car is already accounted for. If there's a part shortage for a particular cars options, the car never starts production. You have to agree that a major corporation like GM wouldn't be operating like a corner hot dog stand that suddenly finds out their out of buns. It was a lot more sophisticated than that. Also, the workers may not have cared about the finished product but they sure cared about their jobs. When production problems show up in dealers under warranty, they are traced back to assembly and the worker that was involved.

Again, I'm not saying it never happened but odd's are slim that any car ever left with the odd spring package that was discussed here. The other part of the problem is the fact that even if it did happen and that car did have the original 7 leaf rear spring, there's no way to ever prove it and the cars are judged from information in the judging guide. I think it would be impossible to ever convince a judge that the spring is original to that car.

The last problem would be the way the car drove and handled with std springs in the front and F41 in the rear. That car would handle terrible. The roll rate in the rear would be so far off that of the front that it would be scary to drive.