[CW3SF]

My previous car was a Gen II Viper. With that car the rockers (valve train) could be changed from 1:6 to 1:7 ratio and it gave a exhaust note a very aggressive chop at idle and added a few horsepower.

Are the LT4 stock cam specs such that a rocker ratio upgrade could induce a noticeable chop without having to do a cam swap?

Here’s an example. This is stock cam and stock heads except for the 1:7 rocker upgrade.

http://youtu.be/_LxjHtuQTec

[Z OH 6]

That's strange. I've never seen a set of higher ratio rockers arms affect the idle that much. You typically gain a little more lift with higher ratio rockers but its typically the LSA of the camshaft that affect idle sound.

[CW3SF]

Originally Posted by Z OH 6

That's strange. I've never seen a set of higher ratio rockers arms affect the idle that much. You typically gain a little more lift with higher ratio rockers but its typically the LSA of the camshaft that affect idle sound.

I’m admittedly not knowledgeable on cam specs but I’d never heard of it either. And the interesting part is that the stock cam in that car is also very friendly to forced induction. That’s why I thought might be worth asking for the LT4

For info:
708 Stock Viper Cam:
Duration at .006” lift intake = 288 deg
Duration at .006” lift exhaust = 296 deg
Duration at .050” intake = 220 deg
Duration at .050” exhaust = 230 deg
Intake Center line = 117 deg
Angle between lobes = 114 deg
Intake lift at lobe = .321
Exhaust lift at lobe= .321

[JasonD]

Lt4’s already use a high 1.8 ratio rocker.

[CW3SF]

Originally Posted by JasonD

Lt4’s already use a high 1.8 ratio rocker.

Wow that’s interesting.

[KingLT1]

All LT engines use 1.8 rockers. As did the LS7.

There is no low hanging fruit on this platform by doing this mod.

You want cam chop then put a cam in with some positive overlap.