C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

68 Corvette Convertible small block or big block?

Thread Tools
 
Search this Thread
 
Old Oct 31, 2012 | 12:03 AM
  #1  
Hub454's Avatar
Hub454
Thread Starter
Advanced
 
Joined: Oct 2012
Posts: 81
Likes: 0
Default 68 Corvette Convertible small block or big block?

I just bought a 68 conv. and it has the axle code of AV with is a 3.08 posi and was listed as a 427. I am trying to find clues to know if this car was originally a big block. It currently has a 350 4spd. One clue I trying to figure out is the tach. It has orange at 5300 and a redline at 5600 does anyone know is the considered redline tach at 5300 or 5600? The trim tag is missing so i am trying to figure out any other way to identify the engine, color, trim this car came with. It does not have a sway bar on the rear. Any thoughts are appreciated.
Reply
Old Oct 31, 2012 | 12:49 AM
  #2  
RickyBerg's Avatar
RickyBerg
Pro
 
Joined: Aug 2010
Posts: 698
Likes: 8
From: Stockholm Sweden
Default

Crawl under the car and check if the rearend yokes coming out from the diff has got the U-clamps (smallblock) or the bolted HD caps (Bigblock).

Anything can offcourse be changed on a car so one can never know for shure but if you have a number of things indicating its a smallblock car its propably one.
Reply
Old Oct 31, 2012 | 11:45 AM
  #3  
Hub454's Avatar
Hub454
Thread Starter
Advanced
 
Joined: Oct 2012
Posts: 81
Likes: 0
Default Rear end caps

The caps look kind of like a u clamp. Do you have any pic of a big block cap?
Reply
Old Oct 31, 2012 | 11:51 AM
  #4  
Easy Mike's Avatar
Easy Mike
Team Owner
Supporting Lifetime
20 Year Member
 
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Default

Originally Posted by Hub454
...I just bought a 68 conv. and it has the axle code of AV with is a 3.08 posi and was listed as a 427...
The AV code is correct for a 68 big block, but your differential may not be original. Big blocks got heavy duty yokes:


...One clue I trying to figure out is the tach. It has orange at 5300 and a redline at 5600 does anyone know is the considered redline tach at 5300 or 5600?...
The red line would be 5600.

...The trim tag is missing so i am trying to figure out any other way to identify the engine, color, trim this car came with...
VIN and trim tag do not identify original engines in the 68s. Trim tag would have codes for the original paint and trim colors and the time/build date. You may be able to peek around door jambs, hood ledges, behind a tail light and find evidence of the original color. Interior color is possibly stock unless you can find obvious evidence of a color change.

...It does not have a sway bar on the rear...
Factory big blocks did, but a PO could have removed the bar at some point in the past. Do your trailing arms have mounting holes for the sway bar link brackets?

What is your VIN?

This is good. Worth the price of a copy:


This is also pretty good:


Order a 68 owner's manual, assembly instruction manual (AIM), and GM chassis service manual for your 68. You're going to want them

Congrats on the 68.


Last edited by Easy Mike; Oct 31, 2012 at 11:59 AM.
Reply
Old Oct 31, 2012 | 12:11 PM
  #5  
restoman1's Avatar
restoman1
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Dec 2010
Posts: 848
Likes: 60
From: CA
Default

The 5600 red line tach is an indicator of the L36 (427/390) or L68 (427/400) engine.

Ed
Reply
Old Oct 31, 2012 | 02:50 PM
  #6  
Hub454's Avatar
Hub454
Thread Starter
Advanced
 
Joined: Oct 2012
Posts: 81
Likes: 0
Default

Thankyou so much for the help its been great!!!! I have always wanted 68-72 converible and now have one. The thing that makes me wonder on a big block are the Tach, rearend #s, original BB hood. But the yokes are ubolt type.

The challenge is do I leave it be and have fun with a good driver or do I tear it down? I will probably tear it down but dont want it to sit for years unfinished. I am wanting to pull the body from the frame and sandblast/paint the frame. That will probably open up a whole can of worms. The book sugguestion are great and I will order them today. I did get a Corvette 1968-1982 Restoration Guide - Prince 2nd addition but it was just OK.
Reply
Old Oct 31, 2012 | 05:12 PM
  #7  
Hub454's Avatar
Hub454
Thread Starter
Advanced
 
Joined: Oct 2012
Posts: 81
Likes: 0
Default

The VIN is 194678s423521. The Fact Book for 68-72 Stingray is disontinued. Do you know where I can find one? Or a replacement book? Thanks
Reply
Old Oct 31, 2012 | 05:41 PM
  #8  
restoman1's Avatar
restoman1
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Dec 2010
Posts: 848
Likes: 60
From: CA
Default

The Fact Book for 68-72 Stingray is disontinued. Do you know where I can find one?
There are two on EBAY, but sit down before you look at the prices. Amazon also shows a few, but again, try not to have a heart attack when you see what they want for them.

Ed

Last edited by restoman1; Oct 31, 2012 at 05:43 PM.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-1

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-2

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-3

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-4

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-5

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-6

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-7

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-8

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-9

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
Old Oct 31, 2012 | 05:48 PM
  #9  
SuperBuickGuy's Avatar
SuperBuickGuy
Melting Slicks
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Aug 2012
Posts: 2,548
Likes: 379
From: Woodinville WA
Default

sit down? $250 made me sit down for a book for my H3....

https://www.paragoncorvette.com/p-35...fact-book.aspx

but $34.00 sounds pretty reasonable
Reply
Old Oct 31, 2012 | 05:54 PM
  #10  
restoman1's Avatar
restoman1
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
Photogenic
 
Joined: Dec 2010
Posts: 848
Likes: 60
From: CA
Default

sit down? $250 made me sit down for a book for my H3....

https://www.paragoncorvette.com/p-35...fact-book.aspx

but $34.00 sounds pretty reasonable
It is, but that's not the book he's looking for.

Ed

Last edited by restoman1; Oct 31, 2012 at 06:02 PM.
Reply

Get notified of new replies

To 68 Corvette Convertible small block or big block?





All times are GMT -4. The time now is 03:58 PM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE