To header or stick with stock headers?
Le Mans Master
Joined: Feb 2009
Posts: 5,169
Likes: 199
From: Your Sister's Bedroom
Le Mans Master
Joined: Mar 2001
Posts: 8,478
Likes: 3,978
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
). For the price, you'd be much better off doing a FlexFuel setup as that will give you some real gains. FlexFuel (E85) will gain a solid 30HP on a Stingray, but the cost isn't cheap at a little under $5K (biggest cost is in the tuning, which is why I'd save for a blower, as that needs tuning as well, so you could do blower and Flex at the same time to save some $).
Le Mans Master
Joined: Feb 2009
Posts: 5,169
Likes: 199
From: Your Sister's Bedroom
Modern cats don't really lose much HP. I think those doing sport cats are seeing 5-10HP. And finding some that won't set a code can be difficult as I've seen people with even the Corsa and other 400 cell sport cats occasionally throw a CEL. Going 200-300 cell will definitely require using an O2 simulator. Going catless will make your significant other (if you have one) never want to ride in your Corvette again (or at least complain about it every time they do ). For the price, you'd be much better off doing a FlexFuel setup as that will give you some real gains. FlexFuel (E85) will gain a solid 30HP on a Stingray, but the cost isn't cheap at a little under $5K (biggest cost is in the tuning, which is why I'd save for a blower, as that needs tuning as well, so you could do blower and Flex at the same time to save some $).
). For the price, you'd be much better off doing a FlexFuel setup as that will give you some real gains. FlexFuel (E85) will gain a solid 30HP on a Stingray, but the cost isn't cheap at a little under $5K (biggest cost is in the tuning, which is why I'd save for a blower, as that needs tuning as well, so you could do blower and Flex at the same time to save some $).My car is on flex and without cats…
Cat delete alone is worth a solid 20hp. Look at a factory cell and tell me it’s not restrictive…
FYI, you can do flex a lot cheaper if you do it yourself. Using a DSX installer and being married to them is not the only option.
I’m going to do a 14:1 440ci sleeved block. I’d rather make 700+whp all motor than with a blower or turbos.
Le Mans Master
Joined: Mar 2001
Posts: 8,478
Likes: 3,978
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
Nice solid 30HP gain with the E85. If I mod my E-Ray, that'll probably be the first thing I do since we have E85 readily available.
Melting Slicks
Joined: Aug 2000
Posts: 2,431
Likes: 1,203
From: Early 2020 Z51 Coupe, Original Owner, Ahwatukee Foothills, AZ
Have greatly enjoyed the 93% efficient hi-flow HJS 200 Cell Cats from Fabspeed over 5 years now without ever ONE CEL. Never a CEL comes from the high amount of rare earth minerals found in the HJS Cats. Just to confirm the OEM Cats have 700 Cells of flow.
Old Goat, Breecher and DBLX is E85 Best Bang correct. My LT2 PCM E85 Flex Tune brought 484rhp/466rtq from Cordes Performance Racing in 12/ 2023.
Advanced
Joined: Sep 2009
Posts: 63
Likes: 10
I agree with everyone else's statements, the best bang for the buck "bolt-on" is an E85 Flex tune, its a consistent 25-30rwhp gain on these cars. A lighter and better flowing catback and air intake are up there as well, but you already have those
If you never intend to go beyond a bolt on car, then headers may not be worth it performance wise, and if you do anyways, make sure you use a brand that actually uses 1 7/8" runners and 3" collectors, I know ARH and Speed Engineering both are actually full 3" at the collector. A lot of the C8 headers out there have small stock size 2.5" collectors. I went with Speed Engineering ones, and for $500 for good quality stainless headers, isn't too bad of a deal.
Melting Slicks
Joined: Jun 2001
Posts: 2,266
Likes: 549
Looking doesn't really tell you anything about how restrictive they are. C8 uses the same cats for LT2 & LT6, so if they flow good enough to support 670HP LT6, I seriously doubt they are a significant restriction. I'm not going to go dig up the posts, but I remember seeing 5-10HP when people dynoed before/after (which is what Google AI result says as well), so would love to see a dyno showing a 20HP gain just for going catless.
Yes, going catless will add a very noticeable smell. I don't mind so much, but I can definitely notice it (and my sense of smell isn't great). My wife has a much better sense of smell, and she would complain every single time.
Nice solid 30HP gain with the E85. If I mod my E-Ray, that'll probably be the first thing I do since we have E85 readily available.
Yes, going catless will add a very noticeable smell. I don't mind so much, but I can definitely notice it (and my sense of smell isn't great). My wife has a much better sense of smell, and she would complain every single time.
Nice solid 30HP gain with the E85. If I mod my E-Ray, that'll probably be the first thing I do since we have E85 readily available.
Last edited by itsonlyairandfuel; Jan 15, 2026 at 11:42 AM. Reason: Add start time
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Le Mans Master
Joined: Feb 2009
Posts: 5,169
Likes: 199
From: Your Sister's Bedroom
Le Mans Master
Joined: Feb 2009
Posts: 5,169
Likes: 199
From: Your Sister's Bedroom
Some of the best shops in the country have posted honest back to back dyno results running with stock manifolds vs headers. On a bolt on car they are absolutely NOT worth buying. Bumped Compression, CNC'd Heads and Cam with a PTR Intake and tuned on E85, then yes, get them.
Melting Slicks
Joined: Jun 2001
Posts: 2,266
Likes: 549
So do you have before and after time slips? DA data to give a clear picture? Or a draggy run?
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 5,730
Likes: 270
From: VENTURA Ca
I'm in the beginning stages of messing with my Eray. I have a Soler TB, Soler controller, AFE intake, ported intake manifold, MBRP valved exhaust and a Fuel-It Bluetooth ethanol analyzer. It's nice to be able to look at my phone and see exactly what my mix is. I've tuned hundreds of C7s but don't want to spend the time learning the Global B platform. I'm getting too old for that. Graham, at Paragon, wrote a 91 Octane "burble" tune to go along with all the mods. I can run E30 on it as well. I also have a full E85 tune for it. Both are a big difference from stock and the "burble" is just right.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
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Supporting Vendor
Joined: Nov 2015
Posts: 1,266
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From: Orange County, NY
I'm in the beginning stages of messing with my Eray. I have a Soler TB, Soler controller, AFE intake, ported intake manifold, MBRP valved exhaust and a Fuel-It Bluetooth ethanol analyzer. It's nice to be able to look at my phone and see exactly what my mix is. I've tuned hundreds of C7s but don't want to spend the time learning the Global B platform. I'm getting too old for that. Graham, at Paragon, wrote a 91 Octane "burble" tune to go along with all the mods. I can run E30 on it as well. I also have a full E85 tune for it. Both are a big difference from stock and the "burble" is just right.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
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http://www.corvetteexhaustsystems.com
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201-575-0861 (cell to call or text)
Your Ultimate Resource For Headers, Exhaust Systems & more for Corvette! I carry Corsa, Kooks, ARH, Borla, Billy Boat, Akrapovic, Capristo & Much More
Platinum Supporting Vendor
Joined: Sep 2001
Posts: 5,730
Likes: 270
From: VENTURA Ca
I don't "work" for A&A. Hell, I barely work at all anymore. 😀 I started A&A 25 years ago.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
Supporting Vendor
Joined: Nov 2015
Posts: 1,266
Likes: 280
From: Orange County, NY
I don't "work" for A&A. Hell, I barely work at all anymore. 😀 I started A&A 25 years ago.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
Le Mans Master
Joined: Feb 2009
Posts: 5,169
Likes: 199
From: Your Sister's Bedroom
I'm in the beginning stages of messing with my Eray. I have a Soler TB, Soler controller, AFE intake, ported intake manifold, MBRP valved exhaust and a Fuel-It Bluetooth ethanol analyzer. It's nice to be able to look at my phone and see exactly what my mix is. I've tuned hundreds of C7s but don't want to spend the time learning the Global B platform. I'm getting too old for that. Graham, at Paragon, wrote a 91 Octane "burble" tune to go along with all the mods. I can run E30 on it as well. I also have a full E85 tune for it. Both are a big difference from stock and the "burble" is just right.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
I'm sort of debating on going full Flex. I can swap tunes in just over a minute. If I don't, I'll probably add a dedicated E30 tune with more timing.
I'm an American Racing Headers dealer, and I'm still not sure about adding those.
Go flex fuel man, it’s worth it!
Safety Car
Joined: Nov 2005
Posts: 4,381
Likes: 939
From: Huntsville Alabama
I don't "work" for A&A. Hell, I barely work at all anymore. 😀 I started A&A 25 years ago.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
I bought my first C8 back in 2021 with the intention of building a system for it. I decided not to do it due to the price point and the time and effort it would take to do it right. THEN I'd have to go through C.A.R.B. certification all over again! That is something I never want to go through again.
I'm quite happy selling 550-600 C5, C6 and C7 systems a year and having time to travel and enjoy myself.
I was surprised you did not come into the C8 market but we all have to draw a line somewhere. I have had many of your systems and they are where great! Hope you enjoy some down time and keep selling the other systems! Pay for that travel ha