YSI Ls9
Thread Starter
Racer
Joined: May 2021
Posts: 468
Likes: 17
From: Northern California
YSI Ls9
I have a stock bottom end Ls9 shortblock going to do headers custom cam and prc heads on e85 should I bump the compresion if so how much 10.5 comp? How far should I push this Ls9 SBE to 900whp? Could I be semi reliable at 1000? If to get to 1000 what pulley should I run has a 2.7 currently on it with a 10% over. Will be on a stock ls3 intake manifold with stock throttle body fuel and driveline part is done for and ready to take this abuse on the street. Could I rev the Ls9 to 7000? Are head studs necessary at 1000whp since Ls9 have bigger head bolts. Thanks guys I also have a 10 rib direct drive
Thread Starter
Racer
Joined: May 2021
Posts: 468
Likes: 17
From: Northern California
Going to just go for 1000 crank which should be 900whp want to be a little safer on a stock bottom end before I push it to 1000+ I’ll go sleeved 427. I do want to rev it to 7000 if that isn’t a issue so I’m wonder if I should go 2.85 pulley or 3.0 I’m going to keep comp right at 10.0. I’ll be on flex only time on 91 is to baby it to get to a e85 station for injectors for sub 900whp I’m thinking 1300cc? I’m doing a walbro 450 in tank with a dsx aux that I have here.
PRC Ls9 Kong heads
custom decent sized blower cam
b and b 1-7:8 headers
e85 flex fuel
comp 10.0
stock ls3 intake and throttle body. Unless I can pick up some power with a 102? And keep boost down so I don’t have pulley it as much
PRC Ls9 Kong heads
custom decent sized blower cam
b and b 1-7:8 headers
e85 flex fuel
comp 10.0
stock ls3 intake and throttle body. Unless I can pick up some power with a 102? And keep boost down so I don’t have pulley it as much
Thread Starter
Racer
Joined: May 2021
Posts: 468
Likes: 17
From: Northern California
so 66k is max propeller speed even though I was told it can go over 70k but just want to retain the life of the blower now. But reliability wise is 200rpm for motor speed make a difference I heard the ls9 pumps don’t like to be over spun
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
Thread Starter
Racer
Joined: May 2021
Posts: 468
Likes: 17
From: Northern California
Hmmm well I set my decision on 900whp just don’t want to deal with a 4 bolt pushing water. Now it’s figuring out if I should spin the motor to 6700 or 6800 or 7000 he’ll maybe even 6500 if it really prolongs the life of the motor
Race Director
Joined: Dec 1999
Posts: 10,230
Likes: 885
From: Alexandria, Virginia, USA VA
with the forged bottom end, billet caps, even chevy rates it to 900 and that is with a rather generous safety margin
you have one of the strongest engines chevy made, I wouldn't hesitate to run it all day at 900 and boost a move to 1k when needed
Race Director
Joined: Dec 1999
Posts: 10,230
Likes: 885
From: Alexandria, Virginia, USA VA
Pro
Joined: Feb 2015
Posts: 528
Likes: 245
From: Chicago IL
With that pulley combo on my 427 I made a hair under 1200whp - make sure you have a big fuel system to support that power on E85 and minimum of 8-rib direct drive setup to avoid belt slip. I would probably run a 3" pulley or larger if 900whp is your target.
Advanced
Joined: Dec 2020
Posts: 72
Likes: 7
I have a stock bottom end Ls9 shortblock going to do headers custom cam and prc heads on e85 should I bump the compresion if so how much 10.5 comp? How far should I push this Ls9 SBE to 900whp? Could I be semi reliable at 1000? If to get to 1000 what pulley should I run has a 2.7 currently on it with a 10% over. Will be on a stock ls3 intake manifold with stock throttle body fuel and driveline part is done for and ready to take this abuse on the street. Could I rev the Ls9 to 7000? Are head studs necessary at 1000whp since Ls9 have bigger head bolts. Thanks guys I also have a 10 rib direct drive