Katech cnc porting bundle for 243s
Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,642
Likes: 7,290
From: CT
I never saw this thread last year but am in for the tune and part throttle results. Having become more familiar with cam specs and head flow charts recently, I have this odd thought in my head that cathedral port heads offer a lot more versatility and efficiency due to air velocity and that, truly, less is often more in ways such as the runners as mentioned. Rec heads flow some sick (intake) numbers, but they need more cr and lift to mask their lack of velocity so the image forming in my head is that the cath heads make better street rippers and the rec heads serve wot functions better (but need a lot of exhaust work).
Eager to hear this one too!
Eager to hear this one too!
Thread Starter
Racer
Joined: Apr 2007
Posts: 452
Likes: 50
Driving feels better everywhere…
I am currently running Speed Density (SD)… getting the VE table dialed in. After the VE table is tight I will reenable the MAF and go down that road.
The cam is relatively small (224/228-114+4). So I am getting great vacuum… 21+ inches at idle.
I have the VE table tuned-in pretty tight up to 4k-rpm.
My static is 10.9 to 1
My DCR is 8.47 to 1
..and Quench is right at .038
… so I am just inside using 93 octane.
… more on tuning to come.
I am currently running Speed Density (SD)… getting the VE table dialed in. After the VE table is tight I will reenable the MAF and go down that road.
The cam is relatively small (224/228-114+4). So I am getting great vacuum… 21+ inches at idle.
I have the VE table tuned-in pretty tight up to 4k-rpm.
My static is 10.9 to 1
My DCR is 8.47 to 1
..and Quench is right at .038
… so I am just inside using 93 octane.
… more on tuning to come.
I never saw this thread last year but am in for the tune and part throttle results. Having become more familiar with cam specs and head flow charts recently, I have this odd thought in my head that cathedral port heads offer a lot more versatility and efficiency due to air velocity and that, truly, less is often more in ways such as the runners as mentioned. Rec heads flow some sick (intake) numbers, but they need more cr and lift to mask their lack of velocity so the image forming in my head is that the cath heads make better street rippers and the rec heads serve wot functions better (but need a lot of exhaust work).
Eager to hear this one too!
Eager to hear this one too!
Thread Starter
Racer
Joined: Apr 2007
Posts: 452
Likes: 50
These combos normally hit 425-430 rwhp. Smaller cam's like this with medium intake runner heads (215 and below...) will get you 400+ rwtq, which is exactly where I wanted to be.
I purposely picked cam specs that landed the IVC event at 42-degrees ( @ .050 )... to keep the LS6 intake peak optimization, in ref. to rpm.
There are a ton of wild off the hook cams that punch higher rwhp, but they always show lower rwtq... like in the 370s. I have driven several and they are slugs below 3500rpms. Just not what I was aiming for. I drive the car daily.
My wideband died... so ordering a new one to tune-in WOT.
On another topic... did anyone take note of the factory cam pitting on the lobe? Scary to see it!!!
Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,642
Likes: 7,290
From: CT
42 is a happy spot, pushes dcr, keeps the map and the tb happy and easy to tune, good throttle response and supports power under the curve. No arguments here. Sounds like a great street grind.
All our lives we chase ridiculous sized cams it seems. Only when we've been there do we realize, no, the lesser duration and mildly smoother lsa is what I want.
All our lives we chase ridiculous sized cams it seems. Only when we've been there do we realize, no, the lesser duration and mildly smoother lsa is what I want.
Safety Car
Joined: Mar 2017
Posts: 3,769
Likes: 940
From: Orlando Florida
I’ve had a couple of pitted cams over the years, mine have usually been from spalling due to poor heat treating. With flat tappets I found the pits were eroding the followers. With other followers I found the surface bridged and didn’t erode. I would think rollers should do the same.
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Running Guns & Moonshine
Joined: Aug 2001
Posts: 12,642
Likes: 7,290
From: CT
Both are solid. I have owned both. The best voodoo seems to be Tony Mamo or BTR worked heads as they focus on velocity and smaller runners which make the best option for all but a dedicated track-only car. Katech is still on that list as well.
Le Mans Master
Joined: Feb 2021
Posts: 6,499
Likes: 4,343
From: Florida
2025 Corvette of the Year Finalist - Unmodified
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Thread Starter
Racer
Joined: Apr 2007
Posts: 452
Likes: 50
AFR 215s are basically another $1150... maybe a little less depending on how much the vendor wants to discount.
... I have used AFRs in the past also... just don't see the extra 1k in performance.
Katech builds the engines used for the GM Corvette Racing team that dominated the U.S. and global GT racing circuits for decades... that is enough for me.
Last edited by Pipedream; Jan 28, 2026 at 07:42 AM.
Thread Starter
Racer
Joined: Apr 2007
Posts: 452
Likes: 50
Update and observations...
It is cold in Western North Carolina... traction is crap!
It is cold in Western North Carolina... traction is crap!
- I never listed the build, completely:
- 2002 ZO6
- 224\228 114+4 cam (Texas Speed)
- 243 heads worked over by Katech (215cc Intake runner 64cc chambers)
- Static 10.9 to 1
- DCR 8.47 to 1
- LG Pro LTs
- Vararam (junk)... blah blah blah...
- 2002 ZO6
- Been a few weeks now and I have been SD tuning my VE table. The VE table is pretty tight (plus or minus 2). I will start MAF tuning this weekend.
- I have been driving daily (grabbing real-life logs)...
- Now that the VE is tight, parking lot driving is a breeze.
- Hot restarts took some changes to the Cranking VE and the Open Loop "After Start", but really not much.
- Power pulls straight from 2000 rpm right to the rev limiter
- Red-light to red-light stuff is just stupid even with 305\30 19s
- As I was hoping... this appears to be a great "I want to drive my car often" build.
Last edited by Pipedream; Feb 6, 2026 at 09:31 AM.
Safety Car
Joined: Jan 2012
Posts: 3,956
Likes: 520
From: Da U.P.
IVC within a half a degree of the cam I have on the shelf, only 3 fewer degrees @ .050" on the intake lobe. . . but with 10.5 degrees less overlap. Yeah that should be a very easy cam to tame. Are you logging g/s of airflow? Probably not with the MAF off, but the PCM will still calculate it regardless.
Racer
Joined: Jul 2010
Posts: 411
Likes: 88
From: Hutto, Texas
Update and observations...
It is cold in Western North Carolina... traction is crap!
It is cold in Western North Carolina... traction is crap!
- I never listed the build, completely:
- 2002 ZO6
- 224\228 114+4 cam (Texas Speed)
- 243 heads worked over by Katech (215cc Intake runner 64cc chambers)
- Static 10.9 to 1
- DCR 8.47 to 1
- LG Pro LTs
- Vararam (junk)... blah blah blah...
- 2002 ZO6
- Been a few weeks now and I have been SD tuning my VE table. The VE table is pretty tight (plus or minus 2). I will start MAF tuning this weekend.
- I have been driving daily (grabbing real-life logs)...
- Now that the VE is tight, parking lot driving is a breeze.
- Hot restarts took some changes to the Cranking VE and the Open Loop "After Start", but really not much.
- Power pulls straight from 2000 rpm right to the rev limiter
- Red-light to red-light stuff is just stupid even with 305\30 19s
- As I was hoping... this appears to be a great "I want to drive my car often" build.
Congrats and enjoy!
Le Mans Master
Joined: Feb 2021
Posts: 6,499
Likes: 4,343
From: Florida
2025 Corvette of the Year Finalist - Unmodified
2024 C5 of the Year Winner- Unmodified
2022 C5 of the Year Finalist - Unmodified