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While the ZZP PCM issue I stand by, this is horsesh1t to the max.
Stock springs, especially cars that are getting 10+ years old and well over 100K+ miles...are getting tired out...and aren't at the same spring rate when they left the factory...and running higher ratio rockers your going to WANT stronger valve springs...why? Because in order to take full advantage of the pitiful HP per $ you gain from a rocker upgrade...your going to need to rev the motor to 6000-6200....whatever you prefer, but stock shift points would be cutting your nose to spite your face. NOT upgrading springs and running a rocker ratio higher than 1.84's...or even modded 1.9's...I'd recommend running LS6 springs, L76 G8 Springs, or Crow 105's...that way you have the peace of mind knowing your not on borrowed time on the worn and tired out factory valve springs that might be sitting around 60-70 lbs...and for the cost of springs...it's kinda one of those...why didn't you do that...like changing the oil and just cleaning the filter and tossing it back on...another one of those...can you run 'em? Sure. Is it the best idea in the long run? IMO, not quite.
Food for thought pulled from ZZP's website:
1.6 is the stock ratio.
1.7 will add some lift to whatever cam you are running. (people will run these with the smaller cams if they add ported heads)
1.8 ratio is intended for stock cams with higher mileage valve springs(or low lift aftermarket cam with ported heads).
1.84 ratio is the highest ratio that you can run on the stock valve springs.
1.9 ratio is for stock cams with aftermarket valve springs & retainers.
1.95 is the most aggressive ratio for a stock cam and obviously requires aftermarket valve springs & retainers.
Last edited by blueguy; 09-27-2011 at 12:20 AM. Reason: Link fail.
Quoted for the truth. Guess I'm pig piling Nick's message. These cars haven't been produced in a while and springs are fatiguing. Change how far and how much something moves now that it has 100k+ miles on it.
If you choose to put higher ratio rockers on older springs, do so knowing that you stand a much better chance of breaking a spring or getting valve float than a fresh engine from the factory.
The points I always tell customers are:
1. Change in amount of movement from the norm.
2. Older fatiguing parts tend to give easier in a #1 situation
3. Liability of the motor is your choice.
4. There's more power in a cylinder with closed valves.
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