Another LS7 manifold vs LT question
Thread Starter
Instructor
Joined: Jun 2019
Posts: 189
Likes: 22
Another LS7 manifold vs LT question
Think I'm at the point very I'm ready to start modding my very close to stock '08 Z51 M6. The only mod currently is a Borla axle back. I was thinking about LS7 manifolds/cats/mid-pipe and a mild cam. This is 99% a street car, might one day see some HPDE, but right now it's almost exclusively a weekend warrior. Useable tq under the curve is probably the goal. I wanna keep it street able in terms of the cam, but really I'm interested in exhaust options.
I've researched on here the gains of the LS7 setup, but LT's provide better gains. I don't NEED to meet emissions, but one day that might change. I understand with LS7 setup that's not really a concern, with LT's I wouldn't mind swapping back to stock for a day IF I ever needed emissions.
Price is also a factor. Seems like the LS7 setup is the more affordable option. Last time I dealt with LT's was on my '02 WS6 and it was a nightmare because
I've researched on here the gains of the LS7 setup, but LT's provide better gains. I don't NEED to meet emissions, but one day that might change. I understand with LS7 setup that's not really a concern, with LT's I wouldn't mind swapping back to stock for a day IF I ever needed emissions.
Price is also a factor. Seems like the LS7 setup is the more affordable option. Last time I dealt with LT's was on my '02 WS6 and it was a nightmare because
- I was 18 and inexperienced
- TSP headers did NOT fit between the block and the car without removing engine mounts
Melting Slicks
Joined: Jul 2004
Posts: 2,721
Likes: 149
From: North Carolina
Sounds like you have similar goals as I did. I installed a full Z06/LS7 setup in my '11 GS. I then gave it to Katech for their Stage II package, which includes a very streetable torquer cam, head work and some other goodies. You'll probably leave a few HP on the table going with the LS7 vs LTs, but I've been very pleased with the LS7 setup. It is quiet, no heat issues, fits perfectly, and looks stock should visual inspections become a concern down the road. Based on feedback from Katech, the LS7 setup showed very close HP/TQ numbers to what they have seen from other LS3's with LTs. I'm not sure if they had done a Stage II package on an LS3 with LS7 exhaust before, but they seemed a bit surprised at how well the LS7 setup flowed.
I managed to get a full LS7 manifolds-to-cans exhaust for $400 and installed the whole thing by myself in my garage on jack stands with hand tools in a day. I sold my stock cats and my NPPs for a $50 net profit, which covered a good portion of the cost of the O2 extensions and gaskets. When all was said and done I did the whole change out for about $20. Hard to beat that performance-to-cost ratio.
Hope that helps in your consideration of your options.
I managed to get a full LS7 manifolds-to-cans exhaust for $400 and installed the whole thing by myself in my garage on jack stands with hand tools in a day. I sold my stock cats and my NPPs for a $50 net profit, which covered a good portion of the cost of the O2 extensions and gaskets. When all was said and done I did the whole change out for about $20. Hard to beat that performance-to-cost ratio.
Hope that helps in your consideration of your options.
Last edited by CrvtBB; Sep 28, 2021 at 09:34 AM.
Le Mans Master
Joined: Mar 2006
Posts: 5,775
Likes: 585
From: Texas
Gains of LT's over the LS7's are going to be dependent on the cam. The more overlap on the cam (i.e. the less streetable), the more the LT's are going to benefit you over the LS7's for peak numbers. If you're going for streetable over max effort, then you're not going to be able to tell the difference in performance except maybe at the track and even then only looking at the timeslip, your butt dyno won't be able to tell the difference.
Le Mans Master
Joined: Mar 2001
Posts: 8,476
Likes: 3,975
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
LS7/9 manifold setup gives a lot of the benefits with none of the drawbacks (heat, fit, passing emissions/visual check, etc). I did it on my previous '13 GS and loved them, and the car made just under 700whp when I sold it (blower). I've kept them on my '12 ZR1 (making 700whp), and there are plenty of ZR1 guys running them up to 800whp (where they seem to start being more of a restriction). I've had LTs on other cars, and it's just not worth the headache for the little bit of extra gain unless you're going for a max effort build.
Thread Starter
Instructor
Joined: Jun 2019
Posts: 189
Likes: 22
I love everything I'm reading. Sounds like I'll definitely be going the LS7/9 route. I didn't know the LS9 manifolds we're also an option. Any idea where to look for these setups? I checked the parts/for sale but everything I saw was close to a grand for just manifolds and cats. I found the manifolds somewhere for $180, but can't find cats that are less than $500 a piece.
Where are they hiding them?! 😂
Where are they hiding them?! 😂
Le Mans Master
Joined: Mar 2001
Posts: 8,476
Likes: 3,975
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
LS7 & LS9 exhaust manifolds are exactly the same. One catch when you're looking, there was a change in 2012 to the cat pipes and the x-pipe (added mini-cats to the x-pipe and changed the connector between the main cat pipes and the x-pipe). Cats are very hard to find anymore because of the recyclers buying them all up.
Race Director
Joined: Oct 2004
Posts: 12,864
Likes: 4,667
LS7/9 manifold setup gives a lot of the benefits with none of the drawbacks (heat, fit, passing emissions/visual check, etc). I did it on my previous '13 GS and loved them, and the car made just under 700whp when I sold it (blower). I've kept them on my '12 ZR1 (making 700whp), and there are plenty of ZR1 guys running them up to 800whp (where they seem to start being more of a restriction). I've had LTs on other cars, and it's just not worth the headache for the little bit of extra gain unless you're going for a max effort build.
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
Safety Car
Joined: May 2016
Posts: 4,667
Likes: 1,849
From: Erlanger, Kentucky
LS7/LS9 exhaust system is an excellent upgrade.
A quality set of headers going into the factory NPP mufflers is the best combination of loudness, power, quietness, and no drone in aftermarket headers (in my opinion). I think Kooks overall have the best fit and ease of installation. I had ARH and they do not fit as well and this is nearly unforgiveable considering the price.
A quality set of headers going into the factory NPP mufflers is the best combination of loudness, power, quietness, and no drone in aftermarket headers (in my opinion). I think Kooks overall have the best fit and ease of installation. I had ARH and they do not fit as well and this is nearly unforgiveable considering the price.
Thread Starter
Instructor
Joined: Jun 2019
Posts: 189
Likes: 22
LS7/LS9 exhaust system is an excellent upgrade.
A quality set of headers going into the factory NPP mufflers is the best combination of loudness, power, quietness, and no drone in aftermarket headers (in my opinion). I think Kooks overall have the best fit and ease of installation. I had ARH and they do not fit as well and this is nearly unforgiveable considering the price.
A quality set of headers going into the factory NPP mufflers is the best combination of loudness, power, quietness, and no drone in aftermarket headers (in my opinion). I think Kooks overall have the best fit and ease of installation. I had ARH and they do not fit as well and this is nearly unforgiveable considering the price.