Re: roller rocker article

From: James Henry (James_Henry@willbros.com)
Date: Wed May 20 1998 - 10:20:16 EDT


>>> <svieth@ameritech.net> 05/19 1:37 PM >>>
> Man, that really makes a Mobile 1 oil change look like a cheap way to gain HP. I wonder why the 1.7 Roller
>Rockers didn't make more of a HP improvement?
>
> -james
> RC R/T

I'll take a little stab at this:

Because you can't just bolt on rockers and hope to magically
cure everything that is restrictive in your vehicle. Is this guy
still running the factory exhaust? Does he have headers?
Did he go to a FABM?

Changing the rockers is part of a larger overall
plan to increase performance. When you add headers,
a cat-back, a high-flow cat or have Sean Meldrum
extrude-hone your intake, you'll be glad that you
have the high-lift rockers.

You have to have all the pieces there to get the big gains.
Check out the five pieces of the "R/T kit" in the
Mopar Performance catalog: filter, computer, cam,
headers, and exhaust system. All five of these
pieces work in harmony to increase performance.

Note: Adding the rockers OR the cam is usually
a *good* idea. Adding both is not always
a *great* idea. Adding the high-lift rockers to the
new cam changes the cam timing and will make the engine think it is
running on a different cam. But that is the topic of another
thread.....

-Scott ;^)

"No, Homer, very few cartoons are broadcast live. It's a
terrible strain on the illustrator's wrist."

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I assumed that the gains in hp (10hp) on Lance's Dak w/ the 1.7 roller rockers would be a maximum expected since he is running a supercharger. No need for a FABM. I also assume that he must have a good cam and exhaust to support the blower application. THis tells me that if you were to install these 1.7 roller rockers on a stock motor you would probably loose hp on the low end and not gain any on the high end.

Also, I was told that higher ratio rockers only increase valve lift and do NOT change the cam timing or duration. Mechanically this makes sense because you are not physically altering the profile of the cam.

Just my Opinon,
James
RC R/T
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