Big flowing heads and cams..why not .600+ cam?
10-08-2002, 11:30 PM
#1
Big flowing heads and cams..why not .600+ cam? If these heads from GTP, TEA and other companies are flowing awesome at .600 lift and greater why does everyone still run .560s - .580 lift cams? If the head peaks at .620 why not run a .615-.620 cam? Wouldn't make sense to run a cam not suited to those 2500 dollar heads. Any thoughts?
Phillip
Phillip
10-08-2002, 11:43 PM
#3
I can shift faster than you.
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Re: Big flowing heads and cams..why not .600+ cam? Phil, alot of it has to do with valvetrain wear. Generally, the more lift you run, the harder it is on parts. Also, valvespring selection and setup becomes more critical as you have to watch out for coil bind,etc.
Also, if the cylinder head peaks out at .620 lift, you generally want to have a cam that has slightly more lift than that. It's all about area under the curve. You can think of it as shifting your car at peak HP instead of a couple hundred rpms past. This is all assuming the head is still flowing fairly well past peak flow. Alot of the ported LS1 heads fall off pretty quickly after .575 lift, while others "stall" after this point and don't fall off to well over .700 lift. It all depends on the shape of the port, valvejob,etc.
So, yes, if the cylinder head flows to .700 lift, you are leaving hp/tq on the table by not properly matching a cam to the heads. However, be prepared to pay careful attention to your valvetrain setup and don't be surprised if you are changing valvesprings regularly.
<small>[ October 08, 2002, 11:44 PM: Message edited by: Jason99T/A ]</small>
Also, if the cylinder head peaks out at .620 lift, you generally want to have a cam that has slightly more lift than that. It's all about area under the curve. You can think of it as shifting your car at peak HP instead of a couple hundred rpms past. This is all assuming the head is still flowing fairly well past peak flow. Alot of the ported LS1 heads fall off pretty quickly after .575 lift, while others "stall" after this point and don't fall off to well over .700 lift. It all depends on the shape of the port, valvejob,etc.
So, yes, if the cylinder head flows to .700 lift, you are leaving hp/tq on the table by not properly matching a cam to the heads. However, be prepared to pay careful attention to your valvetrain setup and don't be surprised if you are changing valvesprings regularly.
<small>[ October 08, 2002, 11:44 PM: Message edited by: Jason99T/A ]</small>
