Ls6 Camshaft Swap

[duc1256]

I got my ls6 cam in today, very very little wear(if any). So is beertestr correct in saying that I can reuse my stock 5.3l pushrods and valve springs? My truck does shift at 5.5k with the Nelson tune. If not, can someone suggest a little bit cheaper valve springs that were recommended earlier? I took 2 weeks off of work to help the wife out with the new baby and to get our 3 year old used to not being the baby anymore or less of a baby. I can have the camshaft in in that time if no new valve train parts are needed, low on paper. Thanks for any help.

[RedHeartbeat]

You need LS6 springs. They're under $60 from Scoggin Dickey Parts Center: GM Performance Parts, GM Crate Engines, GM Goodwrench Crate Motors and Performance Crate Engines

[beertestr]

I got my ls6 cam in today, very very little wear(if any). So is beertestr correct in saying that I can reuse my stock 5.3l pushrods and valve springs? My truck does shift at 5.5k with the Nelson tune. If not, can someone suggest a little bit cheaper valve springs that were recommended earlier? I took 2 weeks off of work to help the wife out with the new baby and to get our 3 year old used to not being the baby anymore or less of a baby. I can have the camshaft in in that time if no new valve train parts are needed, low on paper. Thanks for any help.

EDITTED..

I DIDN'T say that you can reuse your stock springs, I DID ask you what head you have. Depending on what head you had, more importantly what springs you had, I can recommend next steps.

The LS6 springs are the Yellow springs, 12586484. Spring kit from GMPP is 12499224. . Like I noted though, you need the lighter valves to effectively run that cam with those springs up past 6000-6100.. keep an ear out for valve float. The LS6 ran lightweight valves to manage the more aggressive ramps.

Based on your post, you should be fine with running the yellow springs with the heavier valves. Valve control issues are not likely below 6000 RPM. BUT, I gotta still wonder why you would go to this cam if you are shifting at 5500. On a 5.7L, this cam didn't even peak till 6000, peak torque moved up from 4000-4800. The stock shift points on a pickup are 5600 1-2 and 5200 for 2-3 and 3-4. Expect the smaller engine to peak a little higher (assuming your heads are up to the task). I still think that you are not making a great choice for cams, I would not waste the time.

For the power band you are running, I don't think you'd see much from many aftermarket cams. Keep it under 220 degrees @0.050, and go with more lift.



In the power band you are running, you'd see a modest improvement with an LQ9 cam.

[randomhero]

EDITTED..

I DIDN'T say that you can reuse your stock springs, I DID ask you what head you have. Depending on what head you had, more importantly what springs you had, I can recommend next steps.

The LS6 springs are the Yellow springs, 12586484. Spring kit from GMPP is 12499224. . Like I noted though, you need the lighter valves to effectively run that cam with those springs up past 6000-6100.. keep an ear out for valve float. The LS6 ran lightweight valves to manage the more aggressive ramps.

Based on your post, you should be fine with running the yellow springs with the heavier valves. Valve control issues are not likely below 6000 RPM. BUT, I gotta still wonder why you would go to this cam if you are shifting at 5500. On a 5.7L, this cam didn't even peak till 6000, peak torque moved up from 4000-4800. The stock shift points on a pickup are 5600 1-2 and 5200 for 2-3 and 3-4. Expect the smaller engine to peak a little higher (assuming your heads are up to the task). I still think that you are not making a great choice for cams, I would not waste the time.

For the power band you are running, I don't think you'd see much from many aftermarket cams. Keep it under 220 degrees @0.050, and go with more lift.
In the power band you are running, you'd see a modest improvement with an LQ9 cam.

Personally, I would have to disagree with you in a few aspects. There are plenty of people who have bigger cams than 220 duration that run great. If he wanted to stick with the stock converter then that would be a different story, but in that case I wouldn't run anything over a 206/212 or similar.

What makes you say go with a higher lift? If you look at any flow chart for a set of stock 5.3L heads they increasing flow around .450 lift. There is power to be made past that obviously, but very little. You're talking about maybe a 2-3 horse power gain from .550 lift to .600 lift if at all. The heads just don't flow well at that point and it's just a waste and it's added stress on your valvetrain.

As far as the ls6 cam. Even if he's shifting above 6000 he will be fine with the stock length push rods. With that said, I might go with some hardened rods, but the stock LENGTH(7.4) has been proven to work just fine.

As far as the hot cam. I am not a big fan of it. The lobes aren't very aggressive and I have yet to see someone break into the 12s with a hot cam(there may be people out there who have done it, I just haven't seen it).

Everyone is entitled to their own opinion. I don't do this for a living, but my knowledge is a collection of literally thousands of people with different setups and their opinions on their setups. I have seen what works time and time again and what doesn't seem to work or what has yet to be proven to work.

[beertestr]

Personally, I would have to disagree with you in a few aspects. There are plenty of people who have bigger cams than 220 duration that run great. If he wanted to stick with the stock converter then that would be a different story, but in that case I wouldn't run anything over a 206/212 or similar.

He said nothing about changing converters. He said nothing about raising the shift points. Going a heck of a lot bigger with a 5.5k shift point is only going to hurt bottom end torque more than increasing HP in the range he's talking.

What makes you say go with a higher lift? What makes you say go with a higher lift? If you look at any flow chart for a set of stock 5.3L heads they increasing flow around .450 lift. There is power to be made past that obviously, but very little. You're talking about maybe a 2-3 horse power gain from .550 lift to .600 lift if at all. The heads just don't flow well at that point and it's just a waste and it's added stress on your valvetrain.

Keeping duration in check while increasing lift typically does not hurt torque as much while increasing HP. I'll have to read back through the posts, there was another guy jumping on, but I thought I read a post about porting, hence my comments. Look at the bottom. If you THINK that going above 0.450" lift is not worth it, then why be in favor of a LS6 cam that 0.550/0.547?

5.3 LM7
190/191 int/exh @ 0.05" duration
0.466" / 0.457" int/exh lift
114 LSA
2002+ LS6 cam
204/218 int/exh @ 0.05" duration
0.551" / 0.547" int/exh lift
117 LSA
GMPP Hot Cam
218/227 int/exh @ 0.05" duration
0.525" / 0.525" int/exh lift
112 LSA

As far as the ls6 cam. Even if he's shifting above 6000 he will be fine with the stock length push rods. With that said, I might go with some hardened rods, but the stock LENGTH(7.4) has been proven to work just fine.

Why does everybody keep commenting about the pushrods? I never said anything about changing pushrods. I said that the stock springs won't handle the LS6 lift/ramp profile. I also said that the Yellow springs are marginal above 6000 rpm with the heavier, non Ti LS6 valves.

As far as the hot cam. I am not a big fan of it. The lobes aren't very aggressive and I have yet to see someone break into the 12s with a hot cam(there may be people out there who have done it, I just haven't seen it).

No the lobes are not incredibly aggressive, but it makes pretty decent power, with factory springs. It will run a LONG time without any spring, cam lobe wear issues. Yes, it's longer duration, but the LSA is pulled 5 degrees in from the LS6 cam. This should help conserve torque.

Everyone is entitled to their own opinion. I don't do this for a living, but .

My opinion is based on talking with the guys that designed the LS6 cam and valvetrain. I have gone the gamut of looking at factory cam options, from LS6 to the Hot, to LS7 and LS3, so I asked a lot of the same questions the original poster asked, and relayed the answers I was given.

[randomhero]

He said nothing about changing converters. He said nothing about raising the shift points. Going a heck of a lot bigger with a 5.5k shift point is only going to hurt bottom end torque more than increasing HP in the range he's talking.
You're right he didn't say anything about that. That's why I suggested he run something like a 206/212 or something very mild that allows you to run the stock converter. You're also right in that he didn't say anything about changing shift points. Most people change them anyways when they get a custom tune even if they're bone stock. I know most tuners will turn the 1-2 shift up to around 5900-6100 with the stock cam.

A 206/212 is actually more designed for a 5000 pound truck and I know plenty of people using one in their 5.3s.


Keeping duration in check while increasing lift typically does not hurt torque as much while increasing HP. I'll have to read back through the posts, there was another guy jumping on, but I thought I read a post about porting, hence my comments. Look at the bottom. If you THINK that going above 0.450" lift is not worth it, then why be in favor of a LS6 cam that 0.550/0.547?
I never was in favor of the ls6 cam. It's a great turbo cam and a good cheap cam, but it certainly not the best. You will never find me recommending one to someone with an n/a build. I have owned 3 different ls6 cams though and paid $60, $77, and $100 for each of them. That's what makes them so appealing.

As far as the lift I'm aware of what their lift is. I have an 04 ls6 cam sitting right in front of me actually. See above for why I recommend it(it's cheap). My point was in regards to you saying something about increasing lift. My theory hasn't been proven, but I have seen plenty of flow charts and things don't add up. Running a .600 lift cam on stock 5.3L heads just doesn't seem worth it to me.



Why does everybody keep commenting about the pushrods? I never said anything about changing pushrods. I said that the stock springs won't handle the LS6 lift/ramp profile. I also said that the Yellow springs are marginal above 6000 rpm with the heavier, non Ti LS6 valves.
I thought you had said something in regards to the pushrods. Maybe I read it wrong


No the lobes are not incredibly aggressive, but it makes pretty decent power, with factory springs. It will run a LONG time without any spring, cam lobe wear issues. Yes, it's longer duration, but the LSA is pulled 5 degrees in from the LS6 cam. This should help conserve torque.
If by factory springs you're talking about the ls6 springs then quite a few cams will work with those springs. There are plenty of guys running the Tr220 with ls6 springs. That cam has proven to take people well into the 12s.



My opinion is based on talking with the guys that designed the LS6 cam and valvetrain. I have gone the gamut of looking at factory cam options, from LS6 to the Hot, to LS7 and LS3, so I asked a lot of the same questions the original poster asked, and relayed the answers I was given.

It's all just a matter of opinion. I don't have the time or means to do the individual testing. I will say that your ideas go a bit against the grain(not that there's anything wrong with that).

Personally though, all things considered, I'd rather a custom ground cam from Comp or similar spec'ed for a 5000 pound truck rather than a stock cam for a 3300 pound car with a larger engine. Either way, it is an interested discussion, and it's refreshing to hear a different opinion.