4.125 Bore
4.125 Bore Hello, I am thinking about selling my 408ci long block and building a 427, to do this I need a 4.125 bore block.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
you can bore your block another .030 over and run a 4.125 stroke, but thats not the best route. i'd do a resleeved (wet) ls1 block, that will be your cheapest bet. darton's also has there new 4.200 sleeves available soon too.
Originally Posted by term
Hello, I am thinking about selling my 408ci long block and building a 427, to do this I need a 4.125 bore block.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
Originally Posted by Boostaholic
Hello, I am thinking about selling my 408ci long block and building a 427, to do this I need a 4.125 bore block.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
I know the C5R is generally used to do this, but is the LS7 block going to be cheaper? I've heard it comes 4.125 bore stock.
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TECH Resident
Joined: Dec 2004
Posts: 881
Likes: 1
Using aftermarket parts, why would you build a 427 instead of a 441 or 447? Or with a 4.2 bore a 454 or 457?
And doesn't the 2.2" valve LS7 head, with heavily raised, square intake ports, offset pushrods, and matching 90mm intake manifold redefine what a big displacement head should be?
Thanks,
David
And doesn't the 2.2" valve LS7 head, with heavily raised, square intake ports, offset pushrods, and matching 90mm intake manifold redefine what a big displacement head should be?
Thanks,
David
Staging Lane
Joined: Jan 2005
Posts: 57
Likes: 0
Originally Posted by DavidNJ
Using aftermarket parts, why would you build a 427 instead of a 441 or 447? Or with a 4.2 bore a 454 or 457?
And doesn't the 2.2" valve LS7 head, with heavily raised, square intake ports, offset pushrods, and matching 90mm intake manifold redefine what a big displacement head should be?
Thanks,
David
And doesn't the 2.2" valve LS7 head, with heavily raised, square intake ports, offset pushrods, and matching 90mm intake manifold redefine what a big displacement head should be?
Thanks,
David
It is just pushing it. However the idea of an aluminum 457 cid small block is very appealing.
The LS7 heads do seem interesting. Does anyone have flow numbers on them yet? For some reason it seems to me that this engine should be making more hp...I suspect the exhaust system is an issue.
TECH Apprentice
Joined: Oct 2004
Posts: 329
Likes: 0
The LS7 is going to be one where an exhuast and cam change bring up big #'s. With the solid rollers and nice tuned long tubes we will see 600RWHP. Of course additional cubes via stroke will make it more tolerable.
Heads probably need SOME porting, but with a 2.2" intake valve, the ports are probably
big enough to flow as good or better than the BEST LS6 heads. And with porting
probably as good as C5R ( 400CFM ish ).
Heads probably need SOME porting, but with a 2.2" intake valve, the ports are probably
big enough to flow as good or better than the BEST LS6 heads. And with porting
probably as good as C5R ( 400CFM ish ).
Originally Posted by BowtieFreak
For some reason it seems to me that this engine should be making more hp...I suspect the exhaust system is an issue.
Originally Posted by BowtieFreak
Because that would require a 4.125" stroke... you really need a 6.125" rod to get a decent rod to stroke ratio to keep the angles of the rods from sideloading the pistons too hard. This also places the wrist pin very far up the piston skirt, thus causing some potential issues with ring and piston life, as well as, in some cases, ring seal issues.
It is just pushing it.
It is just pushing it.
A 4.200 could shift... Who knows but why take a chance?? 4.125 -4.155 LS2 will be reliable. And at least you can freshen it up a few times... Anybodys block would work for street performance...But I'd be happier if you bought my blocks! 
I have 5 machined sitting on the floor...
Rob we're similarly priced ($3300) Have you had any running yet?
I have 5 machined sitting on the floor...Rob we're similarly priced ($3300) Have you had any running yet?
Originally Posted by SLED28
A 4.200 could shift... Who knows but why take a chance?? 4.125 -4.155 LS2 will be reliable. And at least you can freshen it up a few times... Anybodys block would work for street performance...But I'd be happier if you bought my blocks! I have 5 machined sitting on the floor...
Rob we're similarly priced ($3300) Have you had any running yet?
I have 5 machined sitting on the floor...Rob we're similarly priced ($3300) Have you had any running yet?
Last edited by Rob@ASMotorsports; Feb 11, 2005 at 09:13 PM.
