LS5 or LS6
Thread Starter
Advanced
Joined: May 2008
Posts: 58
Likes: 0
From: Apex NC
LS5 or LS6
Since buying a 70 convertible w/454 HP recently, I have seen numerous times where it is referred to as LS5 and LS6. I originally thought it to be LS5. In overhauling the engine, I found that I had to replace one of the pistons. Hard to find just one, but finally did, but it was listed for a 1971 LS6 454 HP, model L2399F w/.095 Dome. Is it a LS5 or LS6 and why would the piston be shown for a 1971?
Racer
Joined: Feb 2004
Posts: 321
Likes: 0
From: Murrells Inlet SC
The 450-horsepower, LS6 454 never made it into the Corvette for '70- , but was an option in the Chevelle. Then the LS6 showed up as an option for the '71 Corvette, but was de-tuned to 425 horsepower. Even more exotic was the LS7 454, rated at 465 horsepower. It never made it into any Corvettes officially.
The 1970 Corvette had an LS5 454 cu. inch engine ratred at 390 hp. It had hydraulic lifters. I believe the LS6 is a mechanical lifter engine.
The 1970 Corvette had an LS5 454 cu. inch engine ratred at 390 hp. It had hydraulic lifters. I believe the LS6 is a mechanical lifter engine.
Melting Slicks
Joined: Sep 2007
Posts: 2,429
Likes: 0
From: Tucson AZ
The 450-horsepower, LS6 454 never made it into the Corvette for '70- , but was an option in the Chevelle. Then the LS6 showed up as an option for the '71 Corvette, but was de-tuned to 425 horsepower. Even more exotic was the LS7 454, rated at 465 horsepower. It never made it into any Corvettes officially.
The 1970 Corvette had an LS5 454 cu. inch engine ratred at 390 hp. It had hydraulic lifters. I believe the LS6 is a mechanical lifter engine.
The 1970 Corvette had an LS5 454 cu. inch engine ratred at 390 hp. It had hydraulic lifters. I believe the LS6 is a mechanical lifter engine.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
The 70 chevelle LS6 454/450 HP engine was a closed chamber rectangle port iron head, 11.0 compression. Only big block in the 70 vette was the 390 HP LS5, two bolt mains, iron closed chamber heads, hydraulic cam. 1971 vette had two big block options your 365 HP 454 compression was dropped on it for 1971 by using open chamber iron heads.Then there was the LS6 454/425 hp, 4 bolt block, steel crank, forged pistons, aluminum open chamber rectangle heads, mechanical cam. 1971was the only yr for it.
Last edited by Little Mouse; May 8, 2008 at 01:07 AM.
Le Mans Master
Joined: Jul 2006
Posts: 8,117
Likes: 104
From: charlotte north carolina
open heads have the area around the plug relieved, therefore the volume is increased and the cr is reduced (for unleaded gas). some say the open chamber promotes faster and more even flame burn. but to increase cr a domed piston must be used, and some say that interferes with flame burn.
jeff
jeff
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
wall to the chamber close to the valves, open chamber has that same wall laid over angling away from the valves. open chamber helps unshround the valves better on that side of the valve allows the cylinder to pull air around the valves better.
Melting Slicks
Joined: Mar 2005
Posts: 2,187
Likes: 7
From: Chetwynd B.C.
Since buying a 70 convertible w/454 HP recently, I have seen numerous times where it is referred to as LS5 and LS6. I originally thought it to be LS5. In overhauling the engine, I found that I had to replace one of the pistons. Hard to find just one, but finally did, but it was listed for a 1971 LS6 454 HP, model L2399F w/.095 Dome. Is it a LS5 or LS6 and why would the piston be shown for a 1971?
shmoky
