Lt4 hot cam

[nortex]

Will a lt4 hot cam see work in a 98 silverado stock?

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[21Actual]

This has been covered a number of times. 1.6 rockers, and new valve springs/retainers are needed to use this cam in a stock Vortec head. A number of companies manufacture the spring kit that allow for up to .550 lift.

That cam from what I understand isnt ideal if you plan on using your truck as a truck. Also, you would almost certainly need a different torque converter with a higher stall.

And of course a custom tune will be needed. Even with all that, Im not so sure the factory injectors can flow enough to keep up.



I'm no engine builder, this is just the information I have gathered researching cam options for a Vortec 350.


I have decided that Im better off putting the money this would cost towards a 6.0L LS swap.

 

[superdave]

From everything I have read, the LT4 stock production cam looks like a lot better fit for a truck.

 

[slowburb]

This has been covered a number of times. 1.6 rockers, and new valve springs/retainers are needed to use this cam in a stock Vortec head. A number of companies manufacture the spring kit that allow for up to .550 lift.

That cam from what I understand isnt ideal if you plan on using your truck as a truck. Also, you would almost certainly need a different torque converter with a higher stall.

And of course a custom tune will be needed. Even with all that, Im not so sure the factory injectors can flow enough to keep up.



I'm no engine builder, this is just the information I have gathered researching cam options for a Vortec 350.


I have decided that Im better off putting the money this would cost towards a 6.0L LS swap.

Correct for the most part. Why would anyone need 1.6:1 rocker arms to run this cam? Are 1.5:1 ratio rockers incompatible?

No, 1.5:1 rockers are not incompatible. They bolt on and work the valves down and up just like 1.6:1 rockers do, just with about 0.030" less travel.

From everything I have read, the LT4 stock production cam looks like a lot better fit for a truck.

I completely disagree with this statement. This cam is designed for a light vehicle ideally equipped with a manual transmission. I don't claim smarter than GM engineering, but I wouldn't run that cam in anything...much less a Corvette.



Like any "bigger" camshaft, lower rpm torque is compromised for mid to upper rpm torque when valve duration is increased. This doesn't lend itself well to typical street operating rpm, as it shortens the rpm range where the engine is being efficient. In other words, if typical operating range is from off-idle to 4500 rpm, when duration is increased, you should expect for the engine to start making respectable power at a higher rpm, in a direct relationship, where as the duration increases, so does the lower end of the operating range. With less power available at or near idle rpm due to increased valve duration, it is more difficult for the engine to start moving the vehicle, or keep the vehicle moving. In a vehicle with an automatic transmission, a "looser" torque converter is used to allow the engine to rev up closer or into the engine's actual operating range so that it can adequately propel the vehicle into motion from a stop. The LT4 hot cam is in thousands of old school SBC's; both poorly matched and well matched to the rest of the combination. A well thought out combination of parts is what makes a vehicle perform better than in stock configuration.


K.I.S.S. answer: An LT4 hot cam will not work in an otherwise stock pickup truck.

 

[superdave]

Correct for the most part. Why would anyone need 1.6:1 rocker arms to run this cam? Are 1.5:1 ratio rockers incompatible?

No, 1.5:1 rockers are not incompatible. They bolt on and work the valves down and up just like 1.6:1 rockers do, just with about 0.030" less travel.

I completely disagree with this statement. This cam is designed for a light vehicle ideally equipped with a manual transmission. I don't claim smarter than GM engineering, but I wouldn't run that cam in anything...much less a Corvette.



Like any "bigger" camshaft, lower rpm torque is compromised for mid to upper rpm torque when valve duration is increased. This doesn't lend itself well to typical street operating rpm, as it shortens the rpm range where the engine is being efficient. In other words, if typical operating range is from off-idle to 4500 rpm, when duration is increased, you should expect for the engine to start making respectable power at a higher rpm, in a direct relationship, where as the duration increases, so does the lower end of the operating range. With less power available at or near idle rpm due to increased valve duration, it is more difficult for the engine to start moving the vehicle, or keep the vehicle moving. In a vehicle with an automatic transmission, a "looser" torque converter is used to allow the engine to rev up closer or into the engine's actual operating range so that it can adequately propel the vehicle into motion from a stop. The LT4 hot cam is in thousands of old school SBC's; both poorly matched and well matched to the rest of the combination. A well thought out combination of parts is what makes a vehicle perform better than in stock configuration.


K.I.S.S. answer: An LT4 hot cam will not work in an otherwise stock pickup truck.

I was talking about the stock LT4 cam vs the hot cam in a truck application. I personally like the HT383 cam and will eventually be using one of those.

 

[skylark]

From everything I have read, the LT4 stock production cam looks like a lot better fit for a truck.

There is only one guy that I see spouting LT4 production cam and I can tell you that after drinking his chitty kool aid that the LT4 production cam was about my worst possible choice.

 

[slowburb]

I was talking about the stock LT4 cam vs the hot cam in a truck application. I personally like the HT383 cam and will eventually be using one of those.

I know that is the cam you were talking about. It has no place in a pickup motor, much less anything else. As an aside, I'm running the "395" (Marine 350/Ramjet 350/HT383) in my Suburban. It is a bad mammy jammy.

There is only one guy that I see spouting LT4 production cam and I can tell you that after drinking his chitty kool aid that the LT4 production cam was about my worst possible choice.

My point exactly. I know who you're talking about, too. After playing LT4 production cam fanboy, he's now running the "395" cam himself.

 

[99'Subourbon]

Take a moment and listen to Slowburb - following his advice, I'll be going with a 395 cam (HT383) running 1.6 rockers, or something very similar with just slightly more duration (.200/.210).

 

[slowburb]

Small cams rule. And they win, too.

 

[superdave]

I was just trying to talk the guy off the hot cam ledge. Some guys always think long duration cams are always the answer. It doesn't work that way for a torque application.