Demystifying my engine knowledge
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,483
Likes: 1
From: Bay Area CA
Demystifying my engine knowledge
Hey guys,
* What does long block vs short block mean? I am assuming that it's not the same as big block vs small block.
* What does 4 bolt main vs 2 bolt main mean?
* And last but not the least... what type of a block did a 427/390 1969 Vette have?
No big plans now.. just curious and bored
* What does long block vs short block mean? I am assuming that it's not the same as big block vs small block.
* What does 4 bolt main vs 2 bolt main mean?
* And last but not the least... what type of a block did a 427/390 1969 Vette have?
No big plans now.. just curious and bored
Drifting
Joined: Apr 2008
Posts: 1,992
Likes: 56
From: Antioch IL
ok i am no expert but here goes
short block is a replacement engine block with crank shaft, rods and pistons no heads or accessories
a long block is a replacement engine with block, crank shaft, pistons, rods and heads
The difference between 2 bolt and 4 bolt mains are (2 bolts) seriously!!
The 4 bolt mains means that each bearing cap has 4 bolts and the 2 bolt only have 2 bolts on the bearing caps.
As for the last question if i understand correctly you are asking if it is a big or small block. it is a big block.
Hope this helps.
short block is a replacement engine block with crank shaft, rods and pistons no heads or accessories
a long block is a replacement engine with block, crank shaft, pistons, rods and heads
The difference between 2 bolt and 4 bolt mains are (2 bolts) seriously!!
The 4 bolt mains means that each bearing cap has 4 bolts and the 2 bolt only have 2 bolts on the bearing caps.
As for the last question if i understand correctly you are asking if it is a big or small block. it is a big block.
Hope this helps.
Last edited by larryg3; Dec 8, 2009 at 11:44 PM. Reason: spelling
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,483
Likes: 1
From: Bay Area CA
No... I wasn't trying to find if it was a BB or a SB. I want to know how to identify a 427/390 block that will be correct for a late 69 Vette.
Race Director
Joined: Jul 2001
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Instructor
Joined: Apr 2004
Posts: 201
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From: Taunton Ma
Early on in the 69 run they could have come with the following blocks 3935439 and also 3955270 both of these are big blocks. Also both the two had four bolt versions. I think the 512 version started if i recall around November time frame. I do remember someone on the forum claim he had a 512 block with a September date code, thats the only one i have heard of.
Safety Car
Joined: Sep 2007
Posts: 4,452
Likes: 327
From: Indy Indiana
I agree...the 3963512 block both 4 and 2 bolt mains, production began in oct 68 and continued thru the 71 model year.. they were used in corvettes, passenger cars and special COPOs.. you may see some 3955270 and 3935439, but only in early 69 corvettes.. you should have the 3963512 block... check your casting date per the above post.. your 427-390 should be a 2 bolt main with oval port heads..
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Race Director
Joined: Jul 2001
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A given casting number could have been used across many if not all GM cars. Best example is the 0010 small block casting that was used on all GM cars in the 70s, not just Corvette.
I'm referring to the stamped assembly information on the stamp pad at the front right of the engine. This will state where and what day the engine was built, and what type of car with which configuration of engine accessories it was destined for. The pad will also contain a derivative of the original car's VIN.
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,483
Likes: 1
From: Bay Area CA
No. I assume you're not confusing casting number with stamp pad assembly info.
A given casting number could have been used across many if not all GM cars. Best example is the 0010 small block casting that was used on all GM cars in the 70s, not just Corvette.
I'm referring to the stamped assembly information on the stamp pad at the front right of the engine. This will state where and what day the engine was built, and what type of car with which configuration of engine accessories it was destined for. The pad will also contain a derivative of the original car's VIN.
A given casting number could have been used across many if not all GM cars. Best example is the 0010 small block casting that was used on all GM cars in the 70s, not just Corvette.
I'm referring to the stamped assembly information on the stamp pad at the front right of the engine. This will state where and what day the engine was built, and what type of car with which configuration of engine accessories it was destined for. The pad will also contain a derivative of the original car's VIN.
Where do you guys learn so much about this from?
BTW.. do you know of any good books that will help rebuilding a 427 to or close to factory specs?
Is this any good?
Melting Slicks
Joined: May 2009
Posts: 3,079
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2024 C3 of the Year Finalist - Unmodified
Always a good thing to educate yourself before doing something as important as having an engine rebuilt. You really need to hook up with a reputable builder, one who knows these engines very well and is willing to explain to you exactly what should be done and why. The difference in cost between a poor rebuild and a quality rebuild will quickly disappear when you find problems down the road and have to pull the engine again. Just my 2 cents worth.
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,483
Likes: 1
From: Bay Area CA
Always a good thing to educate yourself before doing something as important as having an engine rebuilt. You really need to hook up with a reputable builder, one who knows these engines very well and is willing to explain to you exactly what should be done and why. The difference in cost between a poor rebuild and a quality rebuild will quickly disappear when you find problems down the road and have to pull the engine again. Just my 2 cents worth.
To begin with, I am at this point trying to get myself well educated on the subject.
Race Director
Joined: Jul 2001
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Read, read and read some more! Get hold of all the books you can. The internet holds a huge amount of info although it can sometimes be quite fragmented.
Join the NCRS and soak up all the stuff they offer.
No one person or place or book has 100% to offer.
Join the NCRS and soak up all the stuff they offer.
No one person or place or book has 100% to offer.