Is there, all I hear about is 1.6 and I wonder why? I mean if we can get crazy cams and such that get more lift, why can we only go up .1 in rocker size with a stock cam? In the GTP world, stock size is 1.6 and we can get 1.9's in.

Just trying to understand a bit, that's all.

 

I have seen 1.7's advertised. With the high lift available on roller cams they just aren't needed. The 1.6's will do the job with the present cam profiles and the current design of the SBC heads. Allen

 

Then I guess GM has no clue what they are doing with the LS series engines.....

 

They know exactly what they are doing, higher ratio rockers are far superior to larger lift cams.

 

Care to explain the reasoning to me? I'm curious. I've noticed the trend, but don't know the reasoning behind it.

 

It's difficult to increase the lift on a cam without increasing the duration along with it, because of constraints on the shape of the ramps. Increasing the rocker ratio increases the valve lift for a given lobe lift without increasing the duration.

 

I just assumed we were talking about an L98 engine. Silly me. The LS1 is a completely different design. The cam bore size of the SBC dictates how large the cam lobes can be.

 

Yes, silly you - silly, silly man. When you increase lobe lift, you increase lifter, pushrod travel, and valve travel.... when you increase ratio, you only increase valve travel - much less stress involved, much better durability for all of the associated valvetrain components. Spring compression would be the same on both....

Silly, silly man.


(OHV engines are OHV engines - valvetrain stresses are nearly identical, and the LS series of engines has one of the best designed setups, and there is 100% NO REASON not to duplicate it as much as possible in Gen 1 and 2 engines.)