8k+ rev limit possible with built heads???
04-15-2005, 12:46 PM
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8k+ rev limit possible with built heads??? since the stock ls7 can rev up to 7k, do you guys think with upgraded valvetrain and built head, it can rev up to 8k-8.5k???
high reving engines sound nice.
high reving engines sound nice.
04-15-2005, 04:16 PM
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I believe I remember reading an interview with the chief engineer behind the LS1 engine where he said that the shortblock could take a 7K redline. The valvetrain is the reason it's actually set at 6.
So can a titanium rotating assembly spin to 8? I don't see why not.
So can a titanium rotating assembly spin to 8? I don't see why not.
04-18-2005, 12:30 AM
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The kicker is going to be the valvesprings required to do that. Even though the LS7 will use a titanium valve which is lighter than even the much smaller stainless steel piece that was used on the LS6 head, the hydraulic roller lifter is still a part of the equation here. HR rollers are heavy... and if you get a valvespring stout enough to control the lifter at that RPM level, there's a good chance that the lifter will collapse. So, all of that being said, your best bet would be to convert to solid roller (as far as the valvetrain goes). Something else to consider, however, is the longer stroke of the LS7 compared to the LS1/2/6... that results in increased piston speed and sideloading, which is REALLY hard on parts.
All of that may be moot, though... I recall hearing something about the LS1/6 computers not being able to exceed 8000 RPM. The new LS2/7 computers may be different, I just don't know.
All of that may be moot, though... I recall hearing something about the LS1/6 computers not being able to exceed 8000 RPM. The new LS2/7 computers may be different, I just don't know.
04-18-2005, 01:55 AM
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with a pushrod motor you will have to have a solid roller setup. valve float is pretty much a mainstay in hydraulic rollers above 7400-7500 rpm no matter how built it is. If you step up to a solid roller you might be able to touch that, but why bother revving a 427 that high? It's not needed. Plus those high revving engines that sound nice don't have torque. thats why they need to rev high in the first place.
Nate
Nate
04-18-2005, 11:58 AM
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Last year's CTS-V world challenge cars ran to 7900rpm, before the rules dictated a lower rev limit. These were the cars using LS7 heads and block, destroked to around 3.2". Not sure what tey had for lifters/springs/valves, but it did appear to fit under the factory valve covers (no trick rockers?)
