BP00RedZ

I currently have a T1 cam and am happy with the performance of the car but the cam is tiny by today's standards. I am about to put on a set of heads and would like to upgrade some other parts while I have her open. So here's the question, instead of getting a bigger cam and some nice rocker arms could I see similar results from just upgrading to a 1.75 or 1.8 ratio rocker arm and are there any drawbacks from changing to higher ratio rocker arms instead of the cam itself? The heads are stage II 5.3's that are milled .030 so PVC could be an issue with a big duration cam. The cam specs are .558/.558 221/221 112. Thanks for any help.

Keith

Higher ratio rocker arms will increase lift and the rate at which the valves open and close.

slyws6

Well take this into consideration...

((Cam Lift) / (stock ratio)) * (new ratio) = new lift soooo....

(.558 / 1.7) * 1.75 = .574 lift
(.558 / 1.7) * 1.80 = .591 lift

You can also expect another 3-5 degrees duration depending on which ratio you go with. I'm running a .590/.578 lift cam in mine with unmilled 5.3 heads with no problems, and I know of people running .609 lift on stock deck heads however I'm not sure about the 1.8 ratio but I would venture to say the 1.75 ratio you should be fine. You still need to check the PTV clearance tho!

-Sly

BP00RedZ

Thanks for the good info. What kind of performance and sound difference between these specs?

.558/.558 221/221

.574/.574 224/224

.591/.591 226/226