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Lots of good info :ity:
 

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Lots of good information, however, the cam specs and lift are different from what is listed in SI.
I would be interested if it was a typo, or something changed.
Allthebest, c4c5
 

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Can someone explain how the LS7 can be considered a small block engine? I always thought anything above 5.7 liters was considered a big block.
 

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dallasbboy said:
Can someone explain how the LS7 can be considered a small block engine? I always thought anything above 5.7 liters was considered a big block.
A small block is is not limited to cubic inches to be considered a small block. It's the foot print or architecture of the engine. Your LS-6 can be stroked to 383 inches or so but the outside of the engine doesn't change. The first generation of small block Chevy engines can be built to well over 434 cubic inches with aftermarket parts. By the same token the C5R block is a 427 and it's still a small block.

D.J.
 

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Just looking at these pictures and I see we are having four valve relief pistons being installed in a two valve engine. Can any body explain to me why we need a four valve relief piston? I would think that the two valve reliefs that are not needed/used would be a good hiding place for carbon deposits and so forth. Doesn't GM trust the engine builder's to install the piston in the correct direction? After all, the engine tech building this engine should be the best guy out there to do the job, not some yahoo from out in the parking lot.

D.J.
 

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OneQuickCoupe said:
Just looking at these pictures and I see we are having four valve relief pistons being installed in a two valve engine. Can any body explain to me why we need a four valve relief piston? I would think that the two valve reliefs that are not needed/used would be a good hiding place for carbon deposits and so forth. Doesn't GM trust the engine builder's to install the piston in the correct direction? After all, the engine tech building this engine should be the best guy out there to do the job, not some yahoo from out in the parking lot.

D.J.
That's a good question. I wonder if it has to do with symmetry?
 

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jub jub said:
That's a good question. I wonder if it has to do with symmetry?
That may be one reason if you want to save a few pennies. Aftermarket piston manufactures have built two valves relief piston you decades. They manufacture piston's that come in a balanced set, both static balance and I'm thinking dynamic balance as well. At least they charge enough for them they had better be balanced in both disciplines. A person that would consider buying this car would want to have the best parts installed given the amount of stress that this engine will see. They would have to know we would go to the ends of the earth to find out what we were buying. IMO it appears that they have covered all of the bases except the pistons which I believe are cast as well. Unless I'm missing something here a forged piston would hold up better than a cast part given what this engine will see. A little piston slap in the morning during warm-up would be a small price to pay for having a better piston.

D.J.
 

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Discussion Starter · #14 · (Edited)
My latest analysis of the LS7 engine is that it is probably the closest ever offered for a build up into a racing engine that comes in a production car or offered as a "crate" engine. It will serve as a basis for a fully blueprinted engine with little preperation.

As it is already decked at the factory the block will need little preperation. Here are my points of improvement:

Block:
- Dissassemble and check all tolerences
- Add Forged Pistons
- Add Titanium Wrist Pins with Coating
- Clean up rods
- Lightening and Critical Balancing of Piston/Rod assembly
- Possibly add better Rings ??
- Add +0.610 lift cam with more duration
- Add double roller timing chain or Jesel belt drive
- Aluminum Flywheel
* if more cubic inches are desired then a Darton MID wet sleeve can be used.

Heads:
- Add Rev Kit
- Add Jesel Shaft Rockers at 1.85:1
- Extrude Hone and Polish intake & exhaust ports
- 5 angle racing valve seat
- Add better lifters
- Add better push rods
- Add better/heavier/larger valve springs
- Mill & deck heads 0.010 - 0.030 to increase CR to 11.5 - 12.0
- C5R/C6R valve covers

Oil:
- port, polish & blueprint Oil Pump for higher output flow & pressure
- Increase Oil Reservoir from 8qt. to 10qt. OR
- Add Accusump

Cooling:
- Port, Polish & blueprint water pump
- Port & blueprint T Stat
- Add Waterless Racing Coolant
- Larger 4 core radiator with Integral Engine Oil Cooler
- D/C OEM engine oil cooler & move Tranny cooler to fanned rear unit
- D/C AC
- Katech Idler Pulley

Ignition:
- Add better coils
- Relocate coils
- Add Magnecor KV85 race Wires
- Add & Index Beru Silverstone Racing Plugs
- Add Lightweight Battery
- Add Lightweight alternator
- Reprogramm or replace PCM

Intake Options:
- Halltech Cold Air intake (using hood scoop)
- Halltech Stinger
- Halltech CF Cobra
- Add Billett ported & polished 90x100 oval Throttle Body
- Add 8 individual TB on K or H intake manifold ducted to dual Cobras

Exhaust:
- 1 7/8" primary LT headers with 3" racing Merge Collector
- 3" High Flow CATs
- X Pipe with 3" -> 2/1/2" reduction
- Corsa custom Titanium CAT back (2 1/2")

Fuel:
- Billet High flow Fuel Rails
- Increase Injector Size (decrease duty cycle %)
- High Flow Fuel Pump & Filter
- 1/2" Fuel pickup and fuel line

Wouldn't it be nice if you could send the Performance Build Center a set of forged pistons and a better cam and say,

"Here, use these parts instead."
 

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Thanks for the article. One question though. I have read a number of articles that say the pistons are forged and a number more that say they are cast. Anyone know for sure which it is?
Thanks
 

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Attended most of the GM seminars at the Labor Day NCM Anniversary and remember hearing that the LS7 engine is as close to being a factory built blue printed engine ever. :cheers:
 
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