Biggest bore size
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Registered User
Joined: Aug 2005
Posts: 2
Biggest bore size
Whats the biggest bore you can put in a lt1 block?
I'm thinking of building a high cube max 6000 rpm motor. I just want a car with a ton of torq, like to get 427ci if at all possible.
Want to build an awesome daily driver with auto and 2.73
I know that`s a bit different
I'm thinking of building a high cube max 6000 rpm motor. I just want a car with a ton of torq, like to get 427ci if at all possible.
Want to build an awesome daily driver with auto and 2.73
I know that`s a bit different
Registered User
Joined: Nov 2003
Posts: 1,770
From: Mishawaka, IN
Re: Biggest bore size
Largest safe bore size for an LT1 is 4.060
w/ a 3.875 stroke that would give you 401 ci. That's the largest size that I've ever heard of anyone doing for an LT1. It might be possible to fit a 4" crank, but I doubt it would be a walk in the park, since all the experienced people on here haven't even done it. That would still only give you a 414, though, a 427 would require a 4.125 bore, which won't work unless you sleeve it, which is another thing I've never heard of anyone doing with an LT1. I'm sure part of this is due to gen 1 SBC parts and labor being cheaper and more available, and the fact that the LS1 is receiving more of the large displacement attention now.
To sum it up, getting that size probably is possible with an LT1, but most people that decide to go that big also decide they'd be better off with an SBC or LS1 due to parts availability and the fact that it's already been done many times before (no custom work).
w/ a 3.875 stroke that would give you 401 ci. That's the largest size that I've ever heard of anyone doing for an LT1. It might be possible to fit a 4" crank, but I doubt it would be a walk in the park, since all the experienced people on here haven't even done it. That would still only give you a 414, though, a 427 would require a 4.125 bore, which won't work unless you sleeve it, which is another thing I've never heard of anyone doing with an LT1. I'm sure part of this is due to gen 1 SBC parts and labor being cheaper and more available, and the fact that the LS1 is receiving more of the large displacement attention now.
To sum it up, getting that size probably is possible with an LT1, but most people that decide to go that big also decide they'd be better off with an SBC or LS1 due to parts availability and the fact that it's already been done many times before (no custom work).
Banned
Joined: Apr 2000
Posts: 1,444
Re: Biggest bore size
I've heard of people boring and sleeving out to +.100
At that point the stock block has very little material left for cylinder walls.
Generally, it is recommended that you not exceed +.060 on an LT1 block.
There are aftermarket blocks out there designed to take more.
At that point the stock block has very little material left for cylinder walls.
Generally, it is recommended that you not exceed +.060 on an LT1 block.
There are aftermarket blocks out there designed to take more.
Banned
Joined: May 2003
Posts: 6,661
From: LA (lower Alabama)
Re: Biggest bore size
If ya go .060 I would suggest ya get it sonic checked to make sure your block will do it.
I have been told by my shop that .040 is all they will go and some on the board did the check and found their block to be too thin.
It's better to check than to cave a cyl wall or crack a cyl after assembly and ruin a bunch of good parts.
I have been told by my shop that .040 is all they will go and some on the board did the check and found their block to be too thin.
It's better to check than to cave a cyl wall or crack a cyl after assembly and ruin a bunch of good parts.
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