4 bolt main question.
Thread Starter
Racer
Joined: Jun 2005
Posts: 409
Likes: 13
From: Lavonia Georgia
4 bolt main question.
I've heard that all C3 engines have 4 bolt mains. I have a '68 327-300 I intend to start building but want to make certain I'm not putting more stress on the mains than is appropriate. Instead of dropping the pan to find out, can anyone tell me if I will find 4 bolts?
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Last edited by 68vertible; Sep 20, 2005 at 01:32 PM.
Thread Starter
Racer
Joined: Jun 2005
Posts: 409
Likes: 13
From: Lavonia Georgia
Originally Posted by big_G
I believe you have 2 bolt mains....didn't have 4 'till 1970 with the LT-1 350-370. BTW, 2 bolt mains are ok, especially if you switch to ARP studs, good for maybe 500 crankshaft hp. 
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
The 327 motors never came from the factory with 4 bolt mains. There were plenty made from a 350 block that a 327 crank was laid into. There were 4 bolt mains before 70. 69 saw the first 4 bolt mains in the 302 and the 350 motors.
Race Director
Joined: Dec 2000
Posts: 10,896
Likes: 2
From: CO
Are the mains really the weak point in an engine? I will admit I haven't see alot of blown motors in my limited experience but the ones I have seen certainly haven't been from teh maincaps giving way?
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Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
We had a matching numbers 67 327-350 come in last year with low oil pressure. The block was cracked at each of the middle 3 crank saddles. My machinist says that can happen from excessive detonation, or high rpm with an out-of balance engine.
Racer
Joined: Jul 2005
Posts: 317
Likes: 0
From: PA
It depends on many factors, like what are you looking to do?? I ran my 327 for 2 seasons at the drag, every weekend at 6800rpm with slicks in a 3200lb. car. It was a balanced motor. Ripped it down and had everything checked, nothing moved. Yes mains will go, but so can anything for that matter. I've seen cranks break, rods come apart. If it's done right in the first place you'll be OK.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by 68vertible
I've heard that all C3 engines have 4 bolt mains. Thoughts????
Others here have already answered your other issues.
Melting Slicks
Joined: Dec 2004
Posts: 2,161
Likes: 0
From: pr, frederick md.
Originally Posted by 68vertible
I've heard that all C3 engines have 4 bolt mains. I have a '68 327-300 I intend to start building but want to make certain I'm not putting more stress on the mains than is appropriate. Instead of dropping the pan to find out, can anyone tell me if I will find 4 bolts?
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Le Mans Master
Joined: Apr 1999
Posts: 6,134
Likes: 46
From: Raleigh North Carolina
Originally Posted by pauvil
no 327 four bolts, the 327 and 350 blocks are exactly the same, stick your crank in one and you've got it.
Thread Starter
Racer
Joined: Jun 2005
Posts: 409
Likes: 13
From: Lavonia Georgia
Originally Posted by redc3
all these mods and youre scared to drop the pan????
Drifting
Joined: Nov 2001
Posts: 1,469
Likes: 6
From: 68 427 4.11s Roadster
The only thing I heard came in all vette engines were uncracked cranks. The story goes they would rap them when hanging and the thuds went into bread and butter chevys and rings went into vettes.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Ya know, a good, solid-lifter cam and better heads would make that 327 mouse roar. 
Years ago, I had a 13 second '56 Bel Air two door, using that setup. I had a Muncie 4-speed and 4:56 Posi rear end. It had cheap Mr. Gasket headers and a 780 Holly single pumper ... but also 12:1 compression.
I'd win races and people would be thumping on the hood and doors, looking for glass body panels. That thing was all stock bodied and very, VERY fast for what it was. My shift points were 8500 RPM hence the solid lifters and very low gears.
There's no reason that a motor like that couldn't be built out of what you already have now, and make that Vette haul A$$ if that is what you want. You would be more pleased than using a ZZ block in my opine.
Years ago, I had a 13 second '56 Bel Air two door, using that setup. I had a Muncie 4-speed and 4:56 Posi rear end. It had cheap Mr. Gasket headers and a 780 Holly single pumper ... but also 12:1 compression.I'd win races and people would be thumping on the hood and doors, looking for glass body panels. That thing was all stock bodied and very, VERY fast for what it was. My shift points were 8500 RPM hence the solid lifters and very low gears.
There's no reason that a motor like that couldn't be built out of what you already have now, and make that Vette haul A$$ if that is what you want. You would be more pleased than using a ZZ block in my opine.
Senior Member since 1492
Joined: Aug 2000
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
Originally Posted by 68vertible
I would have to jack it up, drain brand new oil, break the gasket seal, drop the pan, etc. just to find out the answer to a question that I had hoped someone on this forum could provide in 5 minutes based on their immediate knowledge. I've been working on SBC's for 36 years so no...I'm not scared to drop the pan....just didn't seem like the most efficient use of my time and the knowledge available on this forum.
Yeah! I do the same.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Originally Posted by 68vertible
I've heard that all C3 engines have 4 bolt mains. I have a '68 327-300 I intend to start building but want to make certain I'm not putting more stress on the mains than is appropriate. Instead of dropping the pan to find out, can anyone tell me if I will find 4 bolts?
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Okay...I'm editing this post to get an opinion from the group. Starting with a 327-300 that is essentially bone stock, does it make sense to try and build a ZZ4 clone using ZZ4 heads/intake, similar grind roller cam and roller rockers? A build like this will cost a minimum of $2500. But I don't know how much the shorter stroke will affect compression ratio. I had not planned on doing any major changes to the short block other than line bore, new bearings/rings and polished journals. Am I throwing too much $$$ into this build or should I bag the original 327 and leave it alone and just drop in a crate? Thoughts????
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Originally Posted by Techno
The only thing I heard came in all vette engines were uncracked cranks. The story goes they would rap them when hanging and the thuds went into bread and butter chevys and rings went into vettes.
