roller rockers

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02-20-2007, 05:13 PM

#11

OnyxCobra

6th Gear Member

Join Date: Nov 2005

Location: Rochester, NY

Posts: 8,467

RE: roller rockers

I think .540 is too high, i think its more around .530 where you have to start double checking. My lift at .510 with the AFR heads seems to be good, still have to clay it though... if you throw a cam in a stock engine at least you'd probably want to upgrade the valve springs, I would just wait and do heads at the same time.

02-22-2007, 06:57 PM

#12

pastfast125

4th Gear Member

Join Date: Dec 2006

Location:

Posts: 1,097

RE: roller rockers

well I already have cam and spring upgrade, but I was thinkin if I ever have the heads apart or somethin and get some cash and I go to 1.7s if I would have clearance issues. My cam card is out in the car though so I dunno what liftI have, I'll have to go out and get that later.

02-23-2007, 12:31 AM

#13

gspfunk

5th Gear Member

Join Date: Nov 2004

Location: Texas

Posts: 3,834

RE: roller rockers

I ran 1.72's on my E cam [.535 lift on both sides] w/ ported E7's w/ no issues, but you should clay it up yourself to verify that for sure. Like stated above, a higher ratio rocker will increase your lift some [and duration?].

Your duration has more to do w/ PTV than lift, since the piston is at the bottom of the stroke when max lift is acheived.

02-23-2007, 01:59 AM

#14

pastfast125

4th Gear Member

Join Date: Dec 2006

Location:

Posts: 1,097

RE: roller rockers

wow according to that calculation at the top, if I went to 1.7s I'd have lift of .541 exhast and .530 Intake, so yea I better wait till I'm ready to be checking clearances before I try doin that.

02-23-2007, 02:04 AM

#15

LCBlackDep183

3rd Gear Member

Join Date: Jul 2006

Location: Baltimore, MD

Posts: 958

RE: roller rockers

Quote:

ORIGINAL: OnyxCobra

This part:

Quote:

To determine the change in lift when changing rocker arm ratios, divide the lift of the cam by the original rocker ratio (which gives you the lobe lift), then multiply this number by the new rocker ratio. For example, the stock Mustang 5.0L HO cam has .444â€ at the valve. Divide this number by the stock rocker ratio of 1.6 to get the lobe lift, .2775â€ and multiply by the new rocker ratio 1.72, to get the new lift of .477â€.

is an accurate explanation. In short, 1.7 rocker arms basically open the valves farther than 1.6 rockers. The part i just quoted explains how to find the new lift with a 1.7 rocker. Most cams have their lift rated with use with 1.6 rockers, which is why you need to do that math to find the new lift with 1.7s...

Not a innacurate quote, just didnt explain his question is all MAN ONX kick the man why dont you