1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fins"?

**Jim S.** · November 17, 2009, 02:53 AM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Scott,

I can not speak to the 67s ,but the book appears to be incorrect in re finned balancers ending in 65.

Here is a shot of one I have purchased for my 66 , dated C-66.

I bet Joe Lucia will know the exact date they ended the fins. And he and others will know when they stopped using them on Corvettes .

Jim

Ps. I noticed yours is also an A/C car . Can you send me a picture of the Harrison label on you Evap Box if it is still there ?

Attached Files

DSCF1504.jpg (52.4 KB, 86 views)

**Scott S.** · November 17, 2009, 04:30 AM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Jim Schwering (9598)

Scott,

I can not speak to the 67s ,but the book appears to be incorrect in re finned balancers ending in 65.

Here is a shot of one I have purchased for my 66 , dated C-66.

I bet Joe Lucia will know the exact date they ended the fins. And he and others will know when they stopped using them on Corvettes .

Jim

Ps. I noticed yours is also an A/C car . Can you send me a picture of the Harrison label on you Evap Box if it is still there ?

Hi Jim, thanks for the reply. Here are the pictures I took of the Harrison foil label on the evaporator box a couple of weeks ago. I don't know if it's an original foil label or not, it may have come with the box, but I think it's at least 32 years old (1977). That's when the "factory" A/C with correct date code A6 compressor and associated parts for a January '67 car build date (correct dates on foil compressor label and casting date code on A6 end cap) was installed on this January-built car. It came from a '67 Corvette donor car that was being parted out by one of the vendors at the annual summer Bob McDorman Chevrolet dealership Corvette show (Columbus, Ohio).

A6 Compressor casting info:
* K296 * (I think this means November 29, 1966)
B - 1 1 8
6555302

The A/C Foil Sticker on the body of the A6 compressor is pretty worn, but "Model # 5910645" is still clearly visible, which I think is the correct model number. The part of the sticker where the Assembly Date Code is located is almost entirely worn away (the color and printing is worn away, not the foil), but the date looks like it was impact-printed, so the indentations are still visible, and reads:

12 23 62

At first, I thought that meant 1962, but if I understand correctly now, 12 23 62 = December 23, 1966, and the last number ("2") stands for 2nd shift. Any further info or corrections are welcome and appreciated.

The numbers-matching L79 engine (matches VIN tag and frame) has the "HT" suffix (327/350, manual transmission, if I understand correctly), so this was not an A/C car off the assembly line ("HP" or "KH" engine-stamp suffix would indicate L79 with air conditioning, again if I understand correctly).

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**Chris E.** · November 17, 2009, 09:14 AM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Neat car, 67 350 horse air coupe.

The harmonic balancer you have looks just like the one I took of my almost completely original 67 a few years ago. My family has owned the car since 1973.

I think you have the right one, but let's let the thread develop. I've been proven wrong before.

**Jim S.** · November 17, 2009, 01:31 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Thanks Scott.

Jim

**Ray G.** · November 17, 2009, 02:18 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

The numbers-matching L79 engine (matches VIN tag and frame) has the "HT" suffix (327/350, manual transmission, if I understand correctly), so this was not an A/C car off the assembly line ("HP" or "KH" engine-stamp suffix would indicate L79 with air conditioning, again if I understand correctly).
[/FONT][/COLOR][/QUOTE]

Hello;

Believe "HP" suffix is for A/C (C60) with PS (N40)

Ray

**Scott S.** · November 17, 2009, 03:20 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Chris Enstrom (46481)

Neat car, 67 350 horse air coupe. The harmonic balancer you have looks just like the one I took of my almost completely original 67 a few years ago. My family has owned the car since 1973.

I think you have the right one, but let's let the thread develop. I've been proven wrong before.

Thanks for the reply Chris, the plot thickens. It's interesting to find out that yours also had a balancer like this one. The car I'm working on has been in the family since 1976, but it was not driven for about the last 17 years.

I kept reading what the members here and on the CF were saying though, how people who drive their cars every day with correctly rebuilt engines do so on premium pump-gas. So I asked the engine builder to stop everything before he began machining anything

Since then I have had the opportunity to examine the water pump, the heads, the block and now the harmonic balancer up close, trying to figure out what's what. The cam that was in the engine was another surprise. It had the correct 3866954 GM AA TRW (11.0:1) pistons, but a "GM 116" embossed cam, and "F 2 7", with a "6930" casting number (last four digits only of casting # 3896930), which I recently discovered is the 1967 base 300hp engine cam...

The block certainly appears to be the correct L79 327/350hp numbers-matching block, with the "HT" suffix. The receipts don't show anything about changing the cam or anything expensive enough to signify a rebuild going back to February of 1974 (my oldest receipt), but I don't always know exactly what I'm looking at in these old receipts at first, either. Here's the engine stamp, the casting date (L276), the casting number (3892657) and the matching number on the frame, I think this is all good.

If anything looks questionable, somebody please say so, now is the time to find out.

Attached Files

**Scott S.** · November 17, 2009, 03:26 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Jim Schwering (9598)

Thanks Scott.

Jim

You're welcome, if better pictures would help, or if you need any specific information from the sticker that doesn't show up well in the pictures, just let me know and I'll take a closer look at it for you.

**Jimmy B.** · November 17, 2009, 04:04 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Guys,

"HT" engine code was valid for a 67 350 hp with ac. This code was used with & without air conditioning. The HP code indictated the addition of power steering. I have a 67 with HT engine code documented with protecto plate and tank sticker. Note the car did not have factory power steering

This has been discussed in the FORUM before.

Jim Blakely

**Joe L.** · November 17, 2009, 04:48 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Jim Schwering (9598)

Scott,

I can not speak to the 67s ,but the book appears to be incorrect in re finned balancers ending in 65.

Here is a shot of one I have purchased for my 66 , dated C-66.

I bet Joe Lucia will know the exact date they ended the fins. And he and others will know when they stopped using them on Corvettes .

Jim

Ps. I noticed yours is also an A/C car . Can you send me a picture of the Harrison label on you Evap Box if it is still there ?

Jim-----

I hate to disappoint but I'm afraid I don't know when the change was made. However, I have said before that I believe the use of the "finned" balancers ended, in whole or part, prior to the end of the C2 period. Just when it was. I do not know. It's very hard to pin that down because the part number never changed from 1962 right through to the present.

It may also be that both types of balancers were used for awhile----possibly the product of different manufacturers.

**Joe L.** · November 17, 2009, 04:56 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Scott Smith (50839)

I'm trying to identify the (probably incorrect) harmonic balancer that came off of a 1967 L79 engine, to determine whether to have it restored or to begin looking for the correct balancer.

According to the 1967 TIM & JG (Fourth Edition, p. 86):
"The L79 350 hp engines use a heavy 1 3/4 inch thick balancer with an outside diameter of 8 inches. The interior surface has twelve integrally cast fins."

Also, in at least two NCRS Forum Threads, the 1967 L79 harmonic balancer should be (or is correct as) a "finned" balancer:

1967 L79 HT Harmonic Balancer
https://www.forums.ncrs.org/showthre...ancer&uid=2389

327/350HP engine
https://www.forums.ncrs.org/showthre...ering&uid=5910

However, according to "Corvette by the Numbers" (Alan L. Colvin, p. 511-514), the "finned" balancers were only used from 1962-1965 ("third design", date coded) and the 1966-1967 L79 harmonic balancer was NOT "finned" and did NOT have a date code. The 1967 balancer in Colvin's book is close to (but not exactly like) the one I have in the pictures below that came off the '67 L79 I'm in the process of restoring. The inside view of the Fifth design in the "Corvette by the Numbers" book matches the inside view of mine, but the outside view is different in the book than the one I have.

The markings on mine (8 inch diameter) are the following:
One the outside, there is "M - C" at the top (12 o'clock), and "S - 4" at the bottom (at 6 o'clock). On the inside, on the left-hand "spoke", is cast "F 1" on one side of the hole, and "6 - 2" on the other side of the hole. On the inside top spoke (pointing toward 12 o'clock) there is a diamond cast on the right hand side of the hole, and a capital "L" cast on the left-hand side of the hole. I have no idea what these casting numbers mean, and the book does not identify them.

So after all of this, I have three questions:

1. Is it for sure that the only correct harmonic balancer for a 1967 L79 327/350hp engine is a "finned" balancer with a date code, in which case the one that I have is definitely wrong?

2. The TIM & JG appears to be in conflict with the book referenced above. Is the book "Corvette by the Numbers" incorrect when it says the 1962-1965 "third design" was the only 8" finned harmonic SB balancer in a Corvette application, or am I misunderstanding something?

3. Can anyone identify what kind of balancer I actually have, and what application it must have originally come from?

Thanks to anyone who has read this far, comments and replies very much appreciated,

Scott

Scott-----

In your photos of the balancer, it appears that the balancer is completely devoid of paint and rusty. That might just be how it appears in the photo, though. However, if there is, indeed, no trace of paint on the balancer, that would strongly imply a SERVICE origin for the balancer.

On the other hand, the balancer shown on the engine in the chassis pictured does appear to have paint on it and that paint appears well-worn, as would be expected on an original engine this old (by the way, the waterpump has obviously been replaced at some point). If the balancer seen on the engine is the same one pictured separately, then I would say it's almost certainly original to the engine.

**Scott S.** · November 17, 2009, 05:05 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Jimmy Blakely (3742)

Guys,

"HT" engine code was valid for a 67 350 hp with ac. This code was used with & without air conditioning. The HP code indictated the addition of power steering. I have a 67 with HT engine code documented with protecto plate and tank sticker. Note the car did not have factory power steering

This has been discussed in the FORUM before.

Jim Blakely

Hi Jim, thanks for the info. This is good to learn and helps a great deal, because what I read in the books may be out of date, or it may have been incorrect in the first place, and not updated. I was not aware that an "HT" stamped engine could have included A/C. Here is the suffix information I was able to find in 3 separate sources, each arranged a little differently. If anyone has links to other Threads or information showing additions or changes and wants to post them, that would certainly be helpful as far as future archive searches are concerned:

HD | L79 | 350 HP with K19
HE | base | 300 HP with manual trans.
HH | base | 300 HP with K19
HO | base | 300 HP with M35
HP | base or L79 | 300 HP or 350 HP with C60 and N40
HR | base | 300 HP with K19 and M35
HT | L79 | 350 HP with manual trans.
KH | L79 | 350 HP with C60 and K19

327 | 300 | Man. Trans., 3-, 4-Speed, 4BBL | HE
327 | 300 | Man. Trans., 4BBL, A.I.R. | HH
327 | 300 | Powerglide, 4BBL | HO
327 | 300 | Powerglide, 4BBL, A.I.R. | HR
327 | 350 | 4-Speed, Hi-lift Cam, 4BBL, A.I.R. | HD
327 | 350 | 4-Speed, Hi-lift Cam, A/C, P/S, 4BBL | HP
327 | 350 | 4-Speed, Hi-lift Cam, 4BBL | HT
327 | 350 | 4-Speed, Hi-lift Cam, A/C, P/S, 4BBL, A.I.R. | KH

HE | 327 | base | 300 | Holley | Hyd. | Manual |
HH | 327 | base | 300 | Holley | Hyd. | Manual | A.I.R.
HO | 327 | base | 300 | Holley | Hyd. | Powerglide |
HR | 327 | base | 300 | Holley | Hyd. | Powerglide | A.I.R.
HT | 327 | L79 | 350 | Holley | Hyd. | 4-speed |
HD | 327 | L79 | 350 | Holley | Hyd. | 4-speed | A.I.R.
HP | 327 | L79 | 300 | Holley | Hyd. | 4-speed | Air Cond. Power Strg.
KH | 327 | L79 | 350 | Holley | Hyd. | 4-speed | A.I.R. Air Cond. Power Strg.

**Scott S.** · November 17, 2009, 05:28 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Joe Lucia (12484)

Scott-----

In your photos of the balancer, it appears that the balancer is completely devoid of paint and rusty. That might just be how it appears in the photo, though. However, if there is, indeed, no trace of paint on the balancer, that would strongly imply a SERVICE origin for the balancer.

On the other hand, the balancer shown on the engine in the chassis pictured does appear to have paint on it and that paint appears well-worn, as would be expected on an original engine this old (by the way, the waterpump has obviously been replaced at some point). If the balancer seen on the engine is the same one pictured separately, then I would say it's almost certainly original to the engine.

Hi Joe,

The balancer is without paint because it was "cleaned" along with several other engine parts by my former engine builder. The block still has a brownish "grunge" after the cleaning, as do the heads, and this balancer. I have compared the balancer returned to me with close-ups from when it was still on the engine, and based on a close examination of 11 or 12 different "before" pictures, from comparing the size and position of the "divits" (not sure what the circular 'scoops' around the outer ring are called) and various stains, this appears to be the same balancer that was on the engine for at least the last 20 years or more. It used to be painted orange.

I don't know how the brown/rust grunge got under where the paint used to be, but the "stains" visible in some of my "before" pictures (on top of the orange paint) of the balancer appear to be consistent with the stains in the "after" pictures of the balancer, minus the paint (i.e., very similar shaped-stains that were visible while it was still painted orange are still there now, despite the paint having been stripped away).

Regarding the water pump, that's the one I addressed in a separate Thread recently, I think we determined that it was a correct casting number but from 1972.

I'm not sure what to do about the balancer now, whether to send this one to be restored, or to hunt down a finned balancer. If the balancer I have is correct and original, I want to keep it and restore it, but I can't afford to restore incorrect parts, it's expensive enough restoring the right parts

Attached Files

**Scott S.** · November 17, 2009, 05:33 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Joe Lucia (12484)

Jim-----

I hate to disappoint but I'm afraid I don't know when the change was made. However, I have said before that I believe the use of the "finned" balancers ended, in whole or part, prior to the end of the C2 period. Just when it was. I do not know. It's very hard to pin that down because the part number never changed from 1962 right through to the present.

It may also be that both types of balancers were used for awhile----possibly the product of different manufacturers.

If it helps, this car's VIN number corresponds with January 11, 1967 according to the Internet calculators. Then I learned that the "F11" code on the Trim Tag also means "January 11th", if I understand correctly?

**Scott S.** · November 17, 2009, 05:47 PM

Re: 1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fin

Originally posted by Joe Lucia (12484)

Scott-----

In your photos of the balancer, it appears that the balancer is completely devoid of paint and rusty. That might just be how it appears in the photo, though. However, if there is, indeed, no trace of paint on the balancer, that would strongly imply a SERVICE origin for the balancer.

Do the letters and number codes on the balancer help to identify it any?

One the outside, there is "M - C" at the top (12 o'clock), and "S - 4" at the bottom (at 6 o'clock). On the inside, on the left-hand "spoke", is "F 1" on one side of the hole, and "6 - 2" on the other side of the hole. On the inside top spoke (pointing toward 12 o'clock) there is a diamond on the right hand side of the hole, and a capital "L" on the left-hand side of the hole. I have no idea what these casting numbers mean, and the "Corvette by the Numbers" book does not identify them.

1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fins"?

1967 L79 Harmonic Balancer I.D. - Book says "no fins" - NCRS JG & Forum says "fins"?

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