LSX vs Big Block

[Bumblebee2012]

Your power is in the cam and heads. The block and what you do in it are your foundation. Getting the porting right to your rpm and cam is done on a flow bench. You don't want lazy ports, you don't want to hog it out. But you kind of have to develop the entire program together. You can't max port heads/intake at home on a bench because you can't see when your going the right direction with your work or when your destroying a great port. Takes someone with talent and equipment to build a Maxx effort head.

Sent from a Galaxy Note 2, far far away.

[Jims Mongoose]

Originally Posted by Bumblebee2012

Your power is in the cam and heads. The block and what you do in it are your foundation. Getting the porting right to your rpm and cam is done on a flow bench. You don't want lazy ports, you don't want to hog it out. But you kind of have to develop the entire program together. You can't max port heads/intake at home on a bench because you can't see when your going the right direction with your work or when your destroying a great port. Takes someone with talent and equipment to build a Maxx effort head.

Sent from a Galaxy Note 2, far far away.

I hear you and I am in total agreement. That is why I will look for good builder just for that purpose.

What I need to know:
1- is the LS3 block safe at 427 cubic inches making 700 + horsepower.
2- Can I get the 660 horsepower with the mods that I mentioned?
3- How can I get to 725 + HP naturally aspirated and still be street driveable.

Jim

[Bumblebee2012]

I can't help you there, I'm a BB Ford kind of guy :-)

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[Bad70supreme]

I am pretty sure you can safely go to 427 on the stock block. I am not sure about what power level, but there are a few guys on the site that have gone 427. You can get the 427 stroker kit from texas speed!

[VADER SS L99]

Personally I would recommend a ERL re sleeved short block for 427ci or over. People have had issues with the 4.1 inch stroke on a stock LS3 block. With the ERL short block, after market LS7 heads, matching cam and Fast 102 intake, I think 750 crank horsepower is very doable.

[willhe64]

12k for an 800hp big block?

Nope. Lucky to find a used one for that price

[Jims Mongoose]

Originally Posted by VADER SS L99

Personally I would recommend a ERL re sleeved short block for 427ci or over. People have had issues with the 4.1 inch stroke on a stock LS3 block. With the ERL short block, after market LS7 heads, matching cam and Fast 102 intake, I think 750 crank horsepower is very doable.

What is ERL? Is that a company?

When you say people have issues with the 4.1 inch stroke on the stock LS3, does that mean that it doesn't develop enought torque and by making it less square the engine is a better torque performer?

Who can do this kind of work? Are we talking Hennessey, Ligenfelter, SLP?

Relative to the comment from willhe64, I quoted $15000 for a complete LSX 454. Thats what I thought I saw in one of Chevy performance books. It is rated I believe at 740 hP.
I'll check and get back to you guys.

Jim

[gnturboray]

The LSX includes the LS7 427, and yes a maggie, heads and cam for $12k will way out perform the big block.

[2012-1822]

572 Baby! Who doesn't want one!(notice there is no question mark because that wasn't a question)

[Jims Mongoose]

Really, I'm not kidding. I'm kind of new at this. What is a 572?


Jim

[Bumblebee2012]

Originally Posted by Jims Mongoose

Really, I'm not kidding. I'm kind of new at this. What is a 572?


Jim

572 is the size (displacement) of a common Chevy stroker engine.

Sent from a Galaxy Note 2, far far away.

[Jims Mongoose]

My plan for the 1LE which I am looking to purchase.

Bored to 427, thats 54 more cubic inches and shaved heads for increased compression(not sure how much). This should be good for 100 to 120 horsepower.

Headers, cam, cold air, tune should be good for another 100 to 120.
That gives me at best 240 horsepower more for 666 horsepower. A little short of my goal, want 750 at the crank. Am I being to conservative on my estimates or just going in the wrong direction.
Besides the above, what I need to know:
1- is the LS3 block safe at 427 cubic inches making 700 + horsepower.
2- Can I get the 660 horsepower with the mods that I mentioned?
3- How can I get to 725 + HP naturally aspirated and still be street driveable.

Jim[/QUOTE]



You guys have been great, but the above questions and responses would make an awesome thread. LOL. Yes, I am trying to convince you to help me.

Jim

[KCS]

Originally Posted by Jims Mongoose

thanks to both Vader and Bad70. Are you saying that even going to 427 from the current 372 Cubic inches will leave me with an unreliable engine?

My plan was as follows:

Bored to 427, thats 54 more cubic inches and shaved heads for increased compression(not sure how much). This should be good for 100 to 120 horsepower.

Headers, cam, cold air, tune should be good for another 100 to 120.
That gives me at best 240 horsepower more for 666 horsepower. A little short of my goal, want 750 at the crank. Am I being to conservative on my estimates or just going in the wrong direction.

Jim

You can't bore an LS3 to 427ci. You would either have to hone it to 4.070' bore and use a 4.10" crank, or sleeve the block and then you can go to a 4.125" bore and use a 4" crank. Either way, you will need REALLY good heads and a relatively large cam to make 725hp at the flywheel.

Personally, I like the saying, "there is no replacement for displacement". Years ago, SAM built a 468ci BBC (stock crank, rods, and cheapo KB pistons) with oval port heads (to BBC guys, they're about as desirable as LS1 853/341 castings) and a carburetor and made 636hp. Total cost was probably around $6k for everything.

[2012-2SS]

Originally Posted by Jims Mongoose

My plan for the 1LE which I am looking to purchase.

Bored to 427, thats 54 more cubic inches and shaved heads for increased compression(not sure how much). This should be good for 100 to 120 horsepower.

Headers, cam, cold air, tune should be good for another 100 to 120.
That gives me at best 240 horsepower more for 666 horsepower. A little short of my goal, want 750 at the crank. Am I being to conservative on my estimates or just going in the wrong direction.
Besides the above, what I need to know:
1- is the LS3 block safe at 427 cubic inches making 700 + horsepower.
2- Can I get the 660 horsepower with the mods that I mentioned?
3- How can I get to 725 + HP naturally aspirated and still be street driveable.

Jim

You guys have been great, but the above questions and responses would make an awesome thread. LOL. Yes, I am trying to convince you to help me.

Jim[/QUOTE]

Honestly with the money you're putting into that engine you might save $$ by getting a ZL1 and adding headers and a cam.

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