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Discussion Starter #1
I think not, but wanted a second opion. here are the specs:

crower 15510
Grind lobe center 114
adv duration: 275/275
duration at .050: 212/212
lift at 1.6: .531/.531

NRMA F/S rules:

5.0 Engines – .480” maximum valve lift (checked at retainer) and below specified lobe durations and lobe separation angles

Note: Lobe duration is checked at the below specified lobe lifts.

Lobe lift Maximum duration

.050” -- 211

.100” -- 179

.150” -- 148

.200” -- 115



Maximum lobe separation angle – 117 degrees, Minimum lobe separation angle – 115 degrees


thnaks, JP
 

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Discussion Starter #3
well, here are my 2 concerns:

crower states duration at .050 is 212, and the rules say 211.

and

crower states lift at 1.6 is .531 and the rules state 480.

Am I missing something, I'm a little green in this area.

thanks
 

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No...it's not legal..when they mean stock cam lobe...they mean stock cam.
 

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F/S is intended for the stock HO camshaft

only reason they provide the cam data is for the racers to confirm their stock cams will be legal

it does open up the possibility of having a custom cam ground to those specs but why waste the money? its still gonna be a stock cam profile
 

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Discussion Starter #7
I agree with mike g. I would think running a set of 1.7 RR would be more beneficial and cheaper than having a custom cam made.

I think for the money, more ET's could come quicker on other mods.
 

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well the point of my post was the NMRA opened up the possibility for racers to have a cam manufacturer make them a cam IDENTICLE to the factory 100% stock camshaft

the reasoning for this is because they were finding that some of the stock cams were very far out of specs from others. the above numbers are what a stock cam SHOULD BE. providing the specs allows a racer to have a custom cam ground to those specs which makes it sure it is 100% legal rather then trying 10 different stock cams to find one that falls within those specs legally

my point was if you have the time to try a couple different stock cams to find one that will work why waste your money on the custom "stock" cam

there is NO modifications allowed to the cams stock or custom from those specs, im not sure if you fully realize that yet, it has nothing to do with whether they run 1.7 rockers or not. the stock cam with 1.6 rockers has 0.444" lift, that means the cam lobe lift is approximately 0.278" the lobe lift has to be this amount regardless of what rocker arm they are using. the reason they list 0.480" max is because the stock cam with 1.7 rockers is going to have a max lift of 0.472" they also make a 1.72 (0.477") and even a 1.73 ratio rocker arm (0.480") the max 0.480" lift rule allows the 1.73 ratio rockers arms as the maximum allowed

i suggest you take a look at the NMRA Factory Stock rule book if you are thinking of building a car

it can be found at the NMRA site

http://www.nmraracing.com
 
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