Paging Marc Haibeck: Cams

[FU]

The stock cams look real healthy for a 4 valve per cyl. engine.
In comparison the stage 1 cams appear to be pretty radical (IMO).

[XfireZ51]

Originally Posted by FU2

The stock cams look real healthy for a 4 valve per cyl. engine.
In comparison the stage 1 cams appear to be pretty radical (IMO).

Frank,

I forget who I was speaking to while at BG, but they mentioned that the stock motor was actually "overcammed". Could explain why ported heads work well with stock cams.

[Ccmano]

Originally Posted by XfireZ51

Hans,

Are you saying cam profile was the same, just LSA was tighter? It would make sense that if both ports are flowing equally, that you'd want same intake for both primary and secondary. Not sure about exhaust needing any help as I have heard it's pretty efficient already and then if you throw on headers...
You want to make certain you don't over-scavenge robbing power.

This information was published by Mercury Marine in a 1992 bulletin...
H

[FU]

Originally Posted by Pete

I will not get into this with cams on an open forum i might get the boot some might think i'm bashing/insulting them.


Pete

I understand Pete , but also no one would/should think that you are bashing them. Sharing yes.

Originally Posted by XfireZ51

Frank,

I forget who I was speaking to while at BG, but they mentioned that the stock motor was actually "overcammed". Could explain why ported heads work well with stock cams.

IMO the stock cam's are fine for a stock mildly ported 350.

[Pete]

Originally Posted by XfireZ51

Hans,
Not sure about exhaust needing any help as I have heard it's pretty efficient already and then if you throw on headers...
You want to make certain you don't over-scavenge robbing power.

Pete,

Who would give you the boot over a discussion on cams?!

Oh,I forgot this is not a corporate sponsered and run forum.



Exhaust does not need that much help,the exhaust/intake ratio is well over what N/A motor needs.
Do a web search a good ratio for N/A motor is 75-85% we have well above that on a stock head so porting the intake helps bring those #'s closer to perfect.

With big exhaust cams,unless you go with nitrous or turbo/supercharged you will find it hard to tune, idle quality suffers, loose some low end power/torque,drivability suffers .

DRM had .239 intakes with stock exhaust,LPE had B cams .239 IN. .221 EX
You may ask why have Stage III's or LPE C cams because bigger is always better

What i have seen is what GM figured out over 20 years ago keep exhaust duration around 15 degree split.

Pete

[Locobob]

I'm feeling pretty well bashed and insulted Pete, you should be duly booted

I've been thinking about our talk at BG. To bring the lift up to .425 requires taking .035 off the base circle but to get more duration don't you need to take off more than that? Working on figuring out a way to measure valve height in relation to the cam journals... damn you for giving me ideas Pete