C1 & C2 Corvettes General C1 Corvette & C2 Corvette Discussion, Technical Info, Performance Upgrades, Project Builds, Restorations

327 Block Differences?

Thread Tools
 
Search this Thread
 
Old Feb 23, 2013 | 09:04 AM
  #1  
KingD's Avatar
KingD
Thread Starter
Advanced
 
Joined: Jan 2013
Posts: 75
Likes: 0
From: Overland Park Kansas
Default 327 Block Differences?

What is the difference between the 1965 327 block ID 3782870 and the 1965 327 block ID 3858180. Both are small journals.

Can I use either one and rebuild a 327/350?
Reply
Old Feb 23, 2013 | 09:24 AM
  #2  
Ironcross's Avatar
Ironcross
Race Director
10 Year Member
 
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Default

They use the same parts, should fit
Reply
Old Feb 23, 2013 | 10:52 AM
  #3  
MikeM's Avatar
MikeM
Team Owner
15 Year Member
 
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Default

Originally Posted by KingD
What is the difference between the 1965 327 block ID 3782870 and the 1965 327 block ID 3858180. Both are small journals.

Can I use either one and rebuild a 327/350?
The 180 block had thinner cylinder walls than the 870. The factory used the 180 block for engines 250-375 hp.
Reply
Old Feb 23, 2013 | 10:59 AM
  #4  
KingD's Avatar
KingD
Thread Starter
Advanced
 
Joined: Jan 2013
Posts: 75
Likes: 0
From: Overland Park Kansas
Default

That is what I figured, thanks much!

They are offering the block and internal parts with double hump heads for $300. Other than visiable cracks and severe gouges in the cylinder walls, what else should I look for?
Reply
Old Feb 23, 2013 | 11:06 AM
  #5  
MikeM's Avatar
MikeM
Team Owner
15 Year Member
 
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Default

Originally Posted by KingD
That is what I figured, thanks much!

They are offering the block and internal parts with double hump heads for $300. Other than visiable cracks and severe gouges in the cylinder walls, what else should I look for?
Other than a competent machinist to look it over and maybe do some work on it, nothing off hand that I can think of. Maybe one of the machinist types here can suggest something.

Are the main caps on the block?

The price is cheap enough.
Reply
Old Feb 23, 2013 | 01:04 PM
  #6  
65tripleblack's Avatar
65tripleblack
Safety Car
15 Year Member
 
Joined: May 2003
Posts: 4,797
Likes: 239
From: Ocean Township NJ
Default

Originally Posted by KingD
That is what I figured, thanks much!

They are offering the block and internal parts with double hump heads for $300. Other than visiable cracks and severe gouges in the cylinder walls, what else should I look for?

Probably a different block. Scrap iron gets about 200 bucks a ton these days.
Where are the cracks and how deep are the gouges?
Looks like you'll get a pair of double humps for about 280 bucks, which is a fair price.
Reply
Old Feb 23, 2013 | 01:22 PM
  #7  
MikeM's Avatar
MikeM
Team Owner
15 Year Member
 
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Default

Originally Posted by KingD
That is what I figured, thanks much!

They are offering the block and internal parts with double hump heads for $300. Other than visiable cracks and severe gouges in the cylinder walls, what else should I look for?
I hope you meant you were going to look for cracks and gouges, not that you had already seen some in the block?
Reply
Old Feb 23, 2013 | 03:21 PM
  #8  
KingD's Avatar
KingD
Thread Starter
Advanced
 
Joined: Jan 2013
Posts: 75
Likes: 0
From: Overland Park Kansas
Default

Correct, I have now looked at it and no visible signs of cracks in the block and no gouging visible. everything looks fairly clean. So, I have the block, crank, pistons, heads and some extra parts all for $300, now it is time to rebuild it for a fresh motor. Thanks for all of your help.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-1

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

 Joe Kucinski
story-2

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-3

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

 Michael S. Palmer
story-4

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

 Joe Kucinski
story-5

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

 Joe Kucinski
story-6

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

 Verdad Gallardo
story-7

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-8

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-9

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
Old Feb 23, 2013 | 04:30 PM
  #9  
Westlotorn's Avatar
Westlotorn
Le Mans Master
Supporting Lifetime
15 Year Member
 
Joined: Feb 2008
Posts: 6,463
Likes: 1,889
From: Folsom CA
Default

The L79 used a forged crankshaft, I think the low HP 327 used a cast iron crankshaft. Maybe someone on here knows when they used forged vrs cast.
Reply
Old Feb 23, 2013 | 05:00 PM
  #10  
JohnZ's Avatar
JohnZ
Team Owner
Supporting Lifetime Gold
20 Year Member
Veteran: Army
 
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Default

Originally Posted by Westlotorn
The L79 used a forged crankshaft, I think the low HP 327 used a cast iron crankshaft. Maybe someone on here knows when they used forged vrs cast.
As I recall, all Flint-built small-journal 327's had forged cranks; the cranks for SHP engines were also Tufftrided for improved journal surface hardness, and were drilled/tapped for a balancer bolt.
Reply
Old Feb 23, 2013 | 05:16 PM
  #11  
KingD's Avatar
KingD
Thread Starter
Advanced
 
Joined: Jan 2013
Posts: 75
Likes: 0
From: Overland Park Kansas
Default

Good to know as this is a small journal 327.
Reply
Old Feb 23, 2013 | 06:29 PM
  #12  
MikeM's Avatar
MikeM
Team Owner
15 Year Member
 
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Default

Originally Posted by Westlotorn
The L79 used a forged crankshaft, I think the low HP 327 used a cast iron crankshaft. Maybe someone on here knows when they used forged vrs cast.
Only the large journal 327 used the cast crank. '68/later.
Reply
Old Feb 23, 2013 | 08:30 PM
  #13  
jim lockwood's Avatar
jim lockwood
Race Director
15 Year Member
Active Streak: 60 Days
Community Influencer
 
Joined: Feb 2007
Posts: 15,422
Likes: 8,873
From: northern california
C2 of Year Finalist (track prepared) 2019
Default

Originally Posted by MikeM
Only the large journal 327 used the cast crank. '68/later.
And it seems to me that the large journal 327 was a one-year engine. So if, for some reason, you need an LG 327 cast crank, it might be a little tough to find one.
Reply
Old Feb 23, 2013 | 09:05 PM
  #14  
MikeM's Avatar
MikeM
Team Owner
15 Year Member
 
Joined: Mar 2003
Posts: 26,118
Likes: 1,874
From: Greenville, Indiana
Default

Originally Posted by jim lockwood
And it seems to me that the large journal 327 was a one-year engine. So if, for some reason, you need an LG 327 cast crank, it might be a little tough to find one.
It was actually two years. '68-'69. I had to look. Couldn't remember!

Basically it was the same crank as the large journal 307 cranshft and interchangeable with it.
Reply
Old Feb 24, 2013 | 03:35 AM
  #15  
Westlotorn's Avatar
Westlotorn
Le Mans Master
Supporting Lifetime
15 Year Member
 
Joined: Feb 2008
Posts: 6,463
Likes: 1,889
From: Folsom CA
Default

Originally Posted by MikeM
It was actually two years. '68-'69. I had to look. Couldn't remember!

Basically it was the same crank as the large journal 307 cranshft and interchangeable with it.
That is good information. Thanks, I have a cast 327 crank, I was bummed when I pulled it out of a core engine and found the cast and not forged crank, set it aside and never measured. Now I know it should be a large journal. Time to go back and see if that block will make a 383!!! Maybe it is actually one of the rare 350's with the block vent? That would be pretty cool.
Reply
Old Feb 24, 2013 | 02:38 PM
  #16  
kingwoodvette's Avatar
kingwoodvette
Burning Brakes
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2012
Posts: 987
Likes: 170
From: Kingwood Texas
Default

Originally Posted by JohnZ
As I recall, all Flint-built small-journal 327's had forged cranks; the cranks for SHP engines were also Tufftrided for improved journal surface hardness, and were drilled/tapped for a balancer bolt.
John Z--
I have a Flint block cast dateC115 out of an Impala. Do the Chevy 327s also have the forged cranks?
Reply
Old Feb 24, 2013 | 03:16 PM
  #17  
JohnZ's Avatar
JohnZ
Team Owner
Supporting Lifetime Gold
20 Year Member
Veteran: Army
 
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Default

Originally Posted by kingwoodvette
John Z--
I have a Flint block cast dateC115 out of an Impala. Do the Chevy 327s also have the forged cranks?
Yes, they do, if that "5" is 1965 - what's the block casting number?
Reply

Get notified of new replies

To 327 Block Differences?

Old Feb 24, 2013 | 03:31 PM
  #18  
kingwoodvette's Avatar
kingwoodvette
Burning Brakes
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2012
Posts: 987
Likes: 170
From: Kingwood Texas
Default

Block casting number is 3782870
Reply
Old Feb 24, 2013 | 03:36 PM
  #19  
JohnZ's Avatar
JohnZ
Team Owner
Supporting Lifetime Gold
20 Year Member
Veteran: Army
 
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Default

Originally Posted by kingwoodvette
Block casting number is 3782870
Yup, that block was built with a forged crank.
Reply
Old Feb 24, 2013 | 03:57 PM
  #20  
kingwoodvette's Avatar
kingwoodvette
Burning Brakes
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2012
Posts: 987
Likes: 170
From: Kingwood Texas
Default

Good to know. Makes me feel better about my NOM in my 63 especially with its double hump heads. John, thanks for the info. The original "fountain of knowledge!". Randy
Reply




All times are GMT -4. The time now is 02:41 PM.

story-0
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-1
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-2
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-3
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-4
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-5
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-6
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
story-7
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-8
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-9
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE