LS7 Block Limits
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,098
Likes: 1
From: Pollock Pines CA
LS7 Block Limits
Assuming the right rotating assy and valvetrain bits are used, what is the LS7 BLOCK's limits (assume stock 4.125 bore) in terms of FI boost/power levels?
Racer
Joined: Dec 2006
Posts: 276
Likes: 1
From: Los Angeles CA
Depends on the use. A dyno queen will put up with more power than someone who actually uses the car hard. IMO, there's probably a 200-300rwhp difference between what it will take on an occassional basis vs what it will take if you race it regularly.
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
Rough cost is $3000 for sleeves, machine work, install on LS7 block.
OR
$4500 for RHS block which has 6 bolt head provisions, billet mains, good sleeves, more rigid design, etc.
Seems like a no brainer to me. Not to mention the LS7 short blocks if still in good shape bring about $3500.
Le Mans Master
Joined: Jul 2005
Posts: 7,405
Likes: 353
From: New Castle Del.
St. Jude Donor '09
We have made 965rwhp and been 8.81 with our stock ls7 block. I agree with taylor though. If money allows resleeve it. I have used a few from ERL and they work good. Let me know if you need help with anything.
Premium Supporting Vendor
Joined: Oct 2004
Posts: 23,597
Likes: 1,221
From: Providing the most proven supercharger kits for your C5/6/7 609-752-0321
Very impressed with the RHS block for the cost. We have a few builds going together with the RHS standard deck blocks and will be selling the LS7 blocks. Before the RHS block, sleeving the LS7 made a lot of sense.
Rough cost is $3000 for sleeves, machine work, install on LS7 block.
OR
$4500 for RHS block which has 6 bolt head provisions, billet mains, good sleeves, more rigid design, etc.
Seems like a no brainer to me. Not to mention the LS7 short blocks if still in good shape bring about $3500.
Rough cost is $3000 for sleeves, machine work, install on LS7 block.
OR
$4500 for RHS block which has 6 bolt head provisions, billet mains, good sleeves, more rigid design, etc.
Seems like a no brainer to me. Not to mention the LS7 short blocks if still in good shape bring about $3500.
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,098
Likes: 1
From: Pollock Pines CA
Just had a look on the RHS website, looks pretty nice. Aside from the obvious price disparity, how would that compare to DART's billet alum block for a 427ci FI application? power handling, oiling features, ... Just curious.
What kind of setups are you using RHS' blocks for?
What kind of setups are you using RHS' blocks for?
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Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
Just had a look on the RHS website, looks pretty nice. Aside from the obvious price disparity, how would that compare to DART's billet alum block for a 427ci FI application? power handling, oiling features, ... Just curious.
What kind of setups are you using RHS' blocks for?
What kind of setups are you using RHS' blocks for?
RHS block was designed for race applications.
Dart block was designed for bling applications or if you just have too much money.
Former Vendor
Joined: May 2005
Posts: 3,749
Likes: 4
From: Valencia Ca
The RHS block offers premium sleeves, steel caps & main studs, priority main oiling, 6-bolt head mounting, and a host of other durability improvements over the LS7.
Base cost of the RHS is ~$4,500 and final blueprinting operations will be far less than if one used an LS7. Typically the block needs little more than torque-plate honing to finish bore size.
Assuming one already owns a suitable LS7 core, a comparable prepped LS7 (Darton Sleeved & blueprinted) will run ~$2900. At this point one would be wiser and money ahead (IMHO) to sell the LS7 core and buy the RHS.
Melting Slicks
Joined: Dec 2002
Posts: 2,897
Likes: 0
From: Lone Star State
Again, this could go on forever as plenty of guy´s including myself are making great power with a low comp stock block 427. fyi.
It is although a nice upgrade but how many failures have been recorded using the stock ls7 for boosted app??? How much boost???
It is although a nice upgrade but how many failures have been recorded using the stock ls7 for boosted app??? How much boost???
Former Vendor
Joined: May 2003
Posts: 2,173
Likes: 2
From: Dallas Texas
There have been little failures, but one failure is all it takes for me to investigate.
We made over 1000 rwhp on a factory stock sleeved/LS7 block, and 6 texas mile runs at 900 rwhp+ with no issues. That engine is still in service today, and prior to that, it was in a 800 rwhp nitrous Z....
I will say the tune-up has more of an impact than 20 psi of increased cylinder pressure. The limits come from making a mistake. Read up on Formula one engines.... detonation and the streeses on the parts that come from the mistake. 20 psi under controlled combustion is a negligible rise in stress, but when uncontrolled combustion happens, thats when we break parts.
We made over 1000 rwhp on a factory stock sleeved/LS7 block, and 6 texas mile runs at 900 rwhp+ with no issues. That engine is still in service today, and prior to that, it was in a 800 rwhp nitrous Z....
I will say the tune-up has more of an impact than 20 psi of increased cylinder pressure. The limits come from making a mistake. Read up on Formula one engines.... detonation and the streeses on the parts that come from the mistake. 20 psi under controlled combustion is a negligible rise in stress, but when uncontrolled combustion happens, thats when we break parts.
Last edited by Louis @ LG Motorsports; Dec 30, 2009 at 01:50 PM.
Former Vendor
Joined: Jun 2006
Posts: 1,622
Likes: 3
From: Dallas TX
Only available as a complete crate engine. There is no ETA or availability on the LS9 bare block according to my GM rep. New bare LS3 block is available as we have built several engines with these and do have some of the newer windage work around the mains and such but is still wet sump design and does not use the 11mm head bolt.
Few real pics of the RHS for you guys. One really cool thing about the RHS is that I *think* we will be able to remove the lifters withOUT removing the cylinder heads since these windows are so large. I'll try later and confirm this.
Few real pics of the RHS for you guys. One really cool thing about the RHS is that I *think* we will be able to remove the lifters withOUT removing the cylinder heads since these windows are so large. I'll try later and confirm this.
Le Mans Master
Joined: Feb 2007
Posts: 6,674
Likes: 57
From: Mt Pleasant, TN
Safety Car
Joined: Mar 2006
Posts: 4,448
Likes: 4
From: Sarasota Florida
St. Jude Donor '06
Will the RHS block work in an LS7 dry sump application? What do you do for a cam chain?
Is there anything else "special" that has to be done when building these? Special gaskets, fasteners, etc?
Any mods necessary to use one in a C6Z, or is it a straight bolt-in with all factory mounts, accessories, etc?
Is there anything else "special" that has to be done when building these? Special gaskets, fasteners, etc?
Any mods necessary to use one in a C6Z, or is it a straight bolt-in with all factory mounts, accessories, etc?
Le Mans Master
Joined: Oct 2007
Posts: 6,149
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From: Greater Detroit Metro MI, when I'm not travelling.
Former Vendor
Joined: May 2005
Posts: 3,749
Likes: 4
From: Valencia Ca
You of course know that if you are boosting 20PSI, the cylinder pressure is only 20PSI higher prior to ignition... At 20PSI your air/fuel mixture is about 125% denser and will release more than twice as much energy as it would if the engine was N/A... The post ignition combustion pressure is much greater than those initial 20PSI
20 lbs boost = 1829 PSI Cylinder Pressure