[MatthewAMEL]

Greetings all.


Reached a fork in the road for my 1LE. Sell it and replace it or do a full normally aspirated Road Course build.


If I do the build, I am considering Vengeance Racing, Katech or Redline. Transporting the car to any of the three is fine.



After reading a lot of the threads here for years, I do know that I want a sub-.600 lift for valve-train longevity.


Has anyone gotten a build from one of those three shops? Anyone cross-shop them?


Would really appreciate folks with experiences chiming in.


Thanks in advance.

[Puddin]

Originally Posted by MatthewAMEL

Greetings all.


Reached a fork in the road for my 1LE. Sell it and replace it or do a full normally aspirated Road Course build.


If I do the build, I am considering Vengeance Racing, Katech or Redline. Transporting the car to any of the three is fine.



After reading a lot of the threads here for years, I do know that I want a sub-.600 lift for valve-train longevity.


Has anyone gotten a build from one of those three shops? Anyone cross-shop them?


Would really appreciate folks with experiences chiming in.


Thanks in advance.

Go straight to Katech if road course racing is your plan.

[s346k]

Originally Posted by Puddin

Go straight to Katech if road course racing is your plan.

i second this. consider a clutch and trans refresh if the car will be apart.

[Timbo-1LE]

Katech, call Zach. Work was amazing, you could never tell the engine was out of the car. The welds on the headers to NPP look like a robot did them. We tried a GM cam which gave up a bit of power, but it still runs like hell. They even offered replace the cam at a significant discount if I wished. Starts, idles (lopy), but never misses a beat, just as if it came from the factory this way.

[Katech_Zach]

Thank you for the kind words everyone. Matt I can help you out if you have any questions at all.

A note on your valvetrain comment: Lift doesn't necessarily determine valvetrain longevity, it is stability of the system that does. Years back, the higher lift cams were unstable and caused chatter throughout the system, typically from the harsh ramp rates and violent closing events. Over the years, technology has exponentially gotten better. We run nearly .650 lift on every combination with more than 1000 RPM factor of safety without losing control of the valvetrain. Control is key, and as long as the valvetrain is stable, you don't lose any significant wear properties between .575 lift and .650 lift.

The camshaft I am running in my personal ZL1 will be .675 lift on hydraulic roller, and I have 100% confidence I wont have any durability issues.

[ZLAV1N]

+1 for Katech

[MhbGtb]

https://golenengineservice.com/lt1-l...-block-engine/

[Chrome383Z]

Zach what are your thoughts on the higher lift cams and stock heads? There’s been some seat failures on here and it is debated on occasion. Is that anything you guys are seeing?

TSP has a note on their head porting about this, but granted I’m sure their GM is much higher on the PRC stuff so it doesn’t hurt to push that while at the same time protect yourself a little (esp with folks that may set them up poorly).

May give you a call in the next week or so…. Looking for head/cam quote (street/road course as well). Might see what install would be as well. Thanks

[KingLT1]

Originally Posted by Katech_Zach

Thank you for the kind words everyone. Matt I can help you out if you have any questions at all.

A note on your valvetrain comment: Lift doesn't necessarily determine valvetrain longevity, it is stability of the system that does. Years back, the higher lift cams were unstable and caused chatter throughout the system, typically from the harsh ramp rates and violent closing events. Over the years, technology has exponentially gotten better. We run nearly .650 lift on every combination with more than 1000 RPM factor of safety without losing control of the valvetrain. Control is key, and as long as the valvetrain is stable, you don't lose any significant wear properties between .575 lift and .650 lift.

The camshaft I am running in my personal ZL1 will be .675 lift on hydraulic roller, and I have 100% confidence I wont have any durability issues.

Just curious to know what has changed from LS to LT that addresses the valve side loading issue when you run .650+ lift camshafts combined with stock rocker arms? Or are you guys using Roller rockers, changing valve guides, or both? Anybody that has been around these engines dating back to the LS1 know that once you get above .630 lift, the stock rocker arm side loads the valve. It seems Most of the LS cam vendors have dropped back to .600 lift cam shafts for anything with "longevity" as a focal point.

There are a lot of LT1's dropping valves out there in the wild from improper valve control. You just don't read about it here. I touch base with a respected name in the LT game and he sees it quite a bit.

Now please don't take this as anything other then a legit question...it's not a challenge. I know you guys have a solid reputation. I am honestly wanting to know how you reliably run a cam with that kind of lift with "longevity" in mind. For example, Something that can hit the track 6-8 times a year and log 50k miles without needing tore down.

[Motor Fast]

I'm having Katech do a build on my 2002 Camaro SS right now. I went with them due to their engineering side and the C5R and C6R GM work they were involved with.

[SDF62]

Another vote for Katech! They did a build for my 2016 SS last spring....great experience.

[MatthewAMEL]

Originally Posted by KingLT1

Just curious to know what has changed from LS to LT that addresses the valve side loading issue when you run .650+ lift camshafts combined with stock rocker arms? Or are you guys using Roller rockers, changing valve guides, or both? Anybody that has been around these engines dating back to the LS1 know that once you get above .630 lift, the stock rocker arm side loads the valve. It seems Most of the LS cam vendors have dropped back to .600 lift cam shafts for anything with "longevity" as a focal point.

There are a lot of LT1's dropping valves out there in the wild from improper valve control. You just don't read about it here. I touch base with a respected name in the LT game and he sees it quite a bit.

Now please don't take this as anything other then a legit question...it's not a challenge. I know you guys have a solid reputation. I am honestly wanting to know how you reliably run a cam with that kind of lift with "longevity" in mind. For example, Something that can hit the track 6-8 times a year and log 50k miles without needing tore down.

King, reading your posts on this board over the last few years is what convinced me to keep lift to ~.600.


I'll gladly sacrifice some power if I can get a well built motor that can handle track duty.


I've read a few other sources and it seems .600 is the magic number. Lots more failures when lift goes above.

[Katech_Zach]

Originally Posted by KingLT1

Just curious to know what has changed from LS to LT that addresses the valve side loading issue when you run .650+ lift camshafts combined with stock rocker arms? Or are you guys using Roller rockers, changing valve guides, or both? Anybody that has been around these engines dating back to the LS1 know that once you get above .630 lift, the stock rocker arm side loads the valve. It seems Most of the LS cam vendors have dropped back to .600 lift cam shafts for anything with "longevity" as a focal point.

There are a lot of LT1's dropping valves out there in the wild from improper valve control. You just don't read about it here. I touch base with a respected name in the LT game and he sees it quite a bit.

Now please don't take this as anything other then a legit question...it's not a challenge. I know you guys have a solid reputation. I am honestly wanting to know how you reliably run a cam with that kind of lift with "longevity" in mind. For example, Something that can hit the track 6-8 times a year and log 50k miles without needing tore down.

In the LS1 days, the camshaft lobes were MUCH more aggressive, i would classify them as violent. People believed that more power meant faster valvetrain. In other words, open the valves as fast as possible, slam them shut as fast as possible. This allowed you to retain more cylinder pressure on the valve closing event with improved dynamic compression. When you increase valve lift numbers on a "drag race" lobe like that, it is very violent. The valve slams shut and chatters off the seat. The chattering valvetrain wears an hourglass shape into the valve guide. When you get enough valve guide wear, the valve has the ability to wiggle. Once it can wiggle, that is when the "side loading" (more like forward to backwards on the same plane as the rocker body) occurs. Nowadays, valvetrain technology is all about stability, and you get gain back your dynamic compression by increasing static compression.

Roller rockers reduce side loading with decreased friction on the tip of the valve, but increase instability because of the additional mass over the nose. We use stock rocker arms on 99% of our applications because of the minimal weight over the nose.

We spintron all of our valvetrain with a minimum factor of safety of 1000 RPM, so we know that a customer can "over-rev" or "money shift" and not have instable valvetrain. We have taken hydraulic roller valvetrain as high as 9500 RPM in combinations we have tested and developed in-house. These were also around .650 lift.

Stability is also more than just lift, the duration of the cam lobe is just as important. If you have a .650 lift cam, it is much more instable on a 220 @.050 lobe compared to a 250 @.050 lobe. The shape of the cam lobe goes from a "pointy tower" to a rounded dome. This makes ramp rates/valve acceleration much smoother.

We have plenty of durability testing at the .650 lift numbers over the years, we have not had any valve drop issues to date. On rebuilds that were well over-mileaged, we have seen some valve tip wear/damage, but this could be attributed to spring wear. If the spring is heat-cycled and worn, it no longer has the spring pressure it was designed with. If it is too low, the valvetrain can become instable, and chatter can occur. Once chatter occurs, the valve tip can get hammered by the rocker arm.

To date, we have been the most successful with LS7 valve fixes (0 drops in the history of our fix's existence). We had one LT4 drop a valve, but this was due to a spring manufacturing defect. We sent the spring back to the manufacturer, they found porosity within the wire extrusion that caused a stress crack to find its way out over time. This was also a case of a customer being over-mileage on a head service, this drop occurred at 33,000 miles after installation. We typically suggest between 30,000-40,000 miles on a street car, or 40 hours of track mileage on a tracked vehicle. In this case, his car was used in all sorts of conditions, so for him the interval was somewhere in the 20,000 mile range.

Based on our data, there is no risk at running our packages at the higher lift numbers if you maintain the service of your vehicle.

[KingLT1]

I understand that and agree back in the early LS1 days companies were using race lobes and causing a lot of stress and valvetrain instability. Most companies started switching to smoother lobes and lower lift profiles to work around Stock rocker arms which seem to work best in most builds.

However I am specifically speaking about valve sideloading which is a issue on high lift cam shafts with stock rockers. You only covered my question with one sentence stating "roller rockers reduce side loading at the cost of instability". So I am assuming you don't have a solution so you simply deal with the valve guide wear and replace when necessary?

Just because you have stable lobe profiles with high lift at high rpm doesn't mean there won't be added wear from the stock rocker side loading the valve. The only effective way to reduce this is by lowering lift if using stock rocker arms. Hence why some cam companies in the last 6-8 years have started lowering lift on their camshafts....Summit racing, TSP, Cam Motion to name a few.