Big Block Leaf Spring

[Jerry M.]

I have a 66 BB 390 hp. The front stabilizer is 7/8. Rear stabilizer correct. It has a correct ( for seven leaf )rear spring. I am getting it ready for judging. I have been told by several resto people that a seven leaf rear on a big block was not uncommon even with out F 41. Here is the question. What is the prevailing wisdom here? The judging manual says 9 leaf on standard suspension, but standard suspension did not have a rear sway either.
I have researched the archives and found no specific answers. Help. Thanks

[Michael H.]

Re: Big Block Leaf Spring

Jerry,

The NCRS manual is correct. Your 390 HP car should have the standard 9 leaf spring with a rear sway bar. The sway bar was part of the 427 engine option and had nothing to do with heavy duty suspension option which would have included the 7 leaf spring.

Michael

[Michael H.]

Re: Big Block Leaf Spring

Jerry,

The NCRS manual is correct. Your 390 HP car should have the standard 9 leaf spring with a rear sway bar. The sway bar was part of the 427 engine option and had nothing to do with heavy duty suspension option which would have included the 7 leaf spring.

Michael

[John H.]

Re: Big Block Leaf Spring

As Michael indicated, BB's came with the standard 9-leaf rear spring; the 7-leaf spring was part of F41, which was only available with the L-72 engine in '66.

[John H.]

Re: Big Block Leaf Spring

As Michael indicated, BB's came with the standard 9-leaf rear spring; the 7-leaf spring was part of F41, which was only available with the L-72 engine in '66.

[Jerry M.]

Re: Big Block Leaf Spring

Thanks guys for your help. I guess I am looking for a definition of "standard suspension". No matter how you cut it sway bars are part of the suspension. I would read standard to mean " small block" because a 300 hp was "standard". So anything above that to any degree would not be standard (including rear sway). Maybe someone who judges C 2's could chime in. With only two modes in the judging manual you can't have two "standards". Big block standard and small block standard. Just hoping to pick some experienced brains here. Thanks

[Jerry M.]

Re: Big Block Leaf Spring

Thanks guys for your help. I guess I am looking for a definition of "standard suspension". No matter how you cut it sway bars are part of the suspension. I would read standard to mean " small block" because a 300 hp was "standard". So anything above that to any degree would not be standard (including rear sway). Maybe someone who judges C 2's could chime in. With only two modes in the judging manual you can't have two "standards". Big block standard and small block standard. Just hoping to pick some experienced brains here. Thanks

[Michael H.]

Re: Big Block Leaf Spring

Jerry,

It is a bit confusing I suppose, and I tend to write confusing replies to posts. Here it is a different way. Every 66 Corvette ever built that did NOT have have F41 HD suspension with a 7 leaf spring, had a 9 leaf rear spring. The F41 HD suspension with 7 leaf spring was ONLY available with a 425 HP 427 so that automatically eliminates every other 66 ever built from having the 7 leaf spring.

The 9 leaf spring was used on all non F41 cars, including the big block. There was no difference between a big block rear spring and a small block rear spring unless the F41 was ordered with a 425 HP big block. The standard suspension would have included the rear sway bar if either the 390 HP or the 425 HP 427 were ordered.

Soooo....in order to have had a 7 leaf rear spring, the car had to be ordered with two things. A: 427/425 HP B: F41 HD suspension. That's the only way the 7 leaf would have ever been installed at the factory.

Michael

[Michael H.]

Re: Big Block Leaf Spring

Jerry,

It is a bit confusing I suppose, and I tend to write confusing replies to posts. Here it is a different way. Every 66 Corvette ever built that did NOT have have F41 HD suspension with a 7 leaf spring, had a 9 leaf rear spring. The F41 HD suspension with 7 leaf spring was ONLY available with a 425 HP 427 so that automatically eliminates every other 66 ever built from having the 7 leaf spring.

The 9 leaf spring was used on all non F41 cars, including the big block. There was no difference between a big block rear spring and a small block rear spring unless the F41 was ordered with a 425 HP big block. The standard suspension would have included the rear sway bar if either the 390 HP or the 425 HP 427 were ordered.

Soooo....in order to have had a 7 leaf rear spring, the car had to be ordered with two things. A: 427/425 HP B: F41 HD suspension. That's the only way the 7 leaf would have ever been installed at the factory.

Michael

[Dan Pepper]

Re: Big Block Leaf Spring

you have already got it. Both of these two gents are very qualified to answer your question and have almost 90 years combined experience with Corvettes (sorry to point that out, guys ). I suggest you read thier bios (just click on names within posts). Member bios are always an interesting read and say a lot about the level of knowledge & experience of our membership - self depricating though they may be.

Back to the topic: I also have a '66 L36 BB with "standard" suspension. Note I am not a judge - just an enthusiast - so take my note how ever you like.

As mentioned earler, in '66 all BB's came with a rear sway bar as part of the 427 package. In other words, when you orded 427 cubes, your rear suspension was upgraded automatically with a sway bar. Note that you still recieved the standard (same as 300hp issue) 9-leaf rear spring. The F41 package - only available on the high-horse 425hp cars) bought you a thicker front sway bar and a 7 leaf (i.e. stiffer) rear spring in addition to heavy duty shocks all the way around.

[Dan Pepper]

Re: Big Block Leaf Spring

you have already got it. Both of these two gents are very qualified to answer your question and have almost 90 years combined experience with Corvettes (sorry to point that out, guys ). I suggest you read thier bios (just click on names within posts). Member bios are always an interesting read and say a lot about the level of knowledge & experience of our membership - self depricating though they may be.

Back to the topic: I also have a '66 L36 BB with "standard" suspension. Note I am not a judge - just an enthusiast - so take my note how ever you like.

As mentioned earler, in '66 all BB's came with a rear sway bar as part of the 427 package. In other words, when you orded 427 cubes, your rear suspension was upgraded automatically with a sway bar. Note that you still recieved the standard (same as 300hp issue) 9-leaf rear spring. The F41 package - only available on the high-horse 425hp cars) bought you a thicker front sway bar and a 7 leaf (i.e. stiffer) rear spring in addition to heavy duty shocks all the way around.

[Gary B.]

HD rear spring; only 26% of 1966 BB cars had them

If I've done the math right, 26% of 1966 big block cars (2,705 out of 10,374) came with the 7-leaf rear spring. Put another way, roughly 3 out of 4 1966 BB cars came with the 9-leaf spring, also called the standard spring by most people. It seems to be a common misconception that all BB cars had the HD spring.

Gary

[Gary B.]

HD rear spring; only 26% of 1966 BB cars had them

If I've done the math right, 26% of 1966 big block cars (2,705 out of 10,374) came with the 7-leaf rear spring. Put another way, roughly 3 out of 4 1966 BB cars came with the 9-leaf spring, also called the standard spring by most people. It seems to be a common misconception that all BB cars had the HD spring.

Gary

[William C.]

Re: HD rear spring; only 26% of 1966 BB cars had t

Maybe the easiest way to look at it is there are really two "Standard" suspensions, one for smallblocks, and one for big-blocks. All base suspensions had the nine leaf sprind and base shocks. The BB Base added the sway bar as satndard in the base package. F-41 upgraded both packages by changing to the higher rate 7-leaf spring and the stiffer shocks.

[William C.]

Re: HD rear spring; only 26% of 1966 BB cars had t

Maybe the easiest way to look at it is there are really two "Standard" suspensions, one for smallblocks, and one for big-blocks. All base suspensions had the nine leaf sprind and base shocks. The BB Base added the sway bar as satndard in the base package. F-41 upgraded both packages by changing to the higher rate 7-leaf spring and the stiffer shocks.