68 327 large journal 4 bolt main???
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
68 327 large journal 4 bolt main???
Was there ever 4 bolt main large journal 327, I have seen one in a 60 series truck and it there a publication showing this.
Thanks for any help Carl
Thanks for any help Carl
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
They first came out in 68 in conjunction with the 4 bolt 350. GM realized that they had a problem with the small journal cranks breaking when people started hot rodding the 265, 283,302,327
Le Mans Master
Joined: Jan 2006
Posts: 6,506
Likes: 139
From: Butler Pa
I could be wrong, but I was under the impression that there were no 4 bolt 327's and all 302's were large journal.
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Your right there was not any four bolt 327's from the factory. But not all 302's are large journal but most are. There are a few very early 67 models with the small journal.The large journal cranks came about not from broken small steel cranks but rather from the longer stroke of the 350 and cast cranks but proved to be not needed but remains anyway.
Le Mans Master
Joined: Mar 2004
Posts: 7,503
Likes: 1,511
From: Little Rock AR
I do not think there were ever any 327's with 4 bolt mains from the factory. You could build yourself one pretty easily with a large journal 3.25" stroke crank and a 4 bolt main 350 block but none were built by GM. The large journal blocks started exclusively with 350 SS Camaros in 1967. The 327 got large journals in '68 and early '69 before being discontinued but never had 4 bolt mains.
-Mark.
-Mark.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
I don't know about the 4 bolt block, but in 76 I used a large journal forged
327 crank to build myself a 331 using a 4 bolt block, also a friend of mine I shared a shop with built a 348 using a 4.125 400 block he used a large journal 327 crank with a special set of bearings made back then that would allow the 2.45 crank to go in the 2.65 main 400 block.
327 crank to build myself a 331 using a 4 bolt block, also a friend of mine I shared a shop with built a 348 using a 4.125 400 block he used a large journal 327 crank with a special set of bearings made back then that would allow the 2.45 crank to go in the 2.65 main 400 block.
Last edited by Little Mouse; Jun 12, 2008 at 03:31 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Never any 327 Large Journal 4-bolt engines in cars, that is a fact. They can be built with a LG 327 or 307 Crank and a 4-bolt 350 (4" bore) block. I have heard that there were some 60 series type dump trucks built in 69 that did have 327 LG 4-bolt with steel cranks, but I have never seen any proof. The big truck version 68-69 was the only one that had a LG forged crank, they were never in cars stock either to my knowledge.
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Thread Starter
Drifting
Joined: Dec 2005
Posts: 1,360
Likes: 3
From: NORTHEAST
I just talked to a good friend of mine that builds a lot of performance engines and a I asked if he had ever seen a large journal 327 4 bolt main and he had one in the shop about 4 years ago and at that time he went through all the numbers and found it be all original. And thinks the customer still has it.
Rather then argue with me give him a call Bob Baily (Hi Tourque engines) 207-729-7755
And there is another friend of mine that has restored vettes all his life has a book from GM that tells how many were used in the 68 vettes and the 69"s were 350"s
He has built some for his customers but he said there were very few made he has the numbers.
Rather then argue with me give him a call Bob Baily (Hi Tourque engines) 207-729-7755
And there is another friend of mine that has restored vettes all his life has a book from GM that tells how many were used in the 68 vettes and the 69"s were 350"s
He has built some for his customers but he said there were very few made he has the numbers.
Safety Car
Joined: Aug 2006
Posts: 4,102
Likes: 1
From: Forsyth Illinois
I have never seen a large journal 4-bolt 327,but have also, heard of the heavy trucks.Also....heartd the other day that a guy was saling a 68 327 from a Cris Craft boat that was LG,and 4-bolt,but didn't see the engine.
Here is a stock bottom end from mid-68 327/350 horse vette.....
Here is a stock bottom end from mid-68 327/350 horse vette.....
Le Mans Master
Joined: Sep 2000
Posts: 9,078
Likes: 7
From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
My best friend in high school had one of those 327 boat motors in his 70 Z28. He pulled the LT1 for safe keeping and would spin the hell out of that solid crank 327 motor. It was painful riding around. The think would shear rear studs. Pretty sure it was a four bolt main, because it was all he talked about.
Instructor
Joined: Apr 2007
Posts: 148
Likes: 0
From: Leavenworth Kansas
I have such a long block for sale (1968). RPO is L79. 2-bolt main block but the forged crank is large journal (or some folks call them "medium" journal cranks; guess there are cranks with even larger journals.)
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
400's are larger, but most just refer to small and large on 350's and smaller. I had a 327 large journal forged crank once, too. Should have kept it and used it with spacers in a 400 block, but when somebody waves cash in front of me...