427 experts
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Take a look at this site if your interested - http://www.empirenet.com/pkelley2/DynamicCR.html
You can download your own DCR calculation software that I like a lot better than the KB version.
You can download your own DCR calculation software that I like a lot better than the KB version.
I like Kelley's comprehensive calculator also.
FWIW, the moderate ~10.3:1 427 pump-gas (92 octane) mill I'm putting together this time around should come in at just under 8:1 tDCR, which I don't consider too low for my purposes. And IIRC, elle88's N+ZL-1S cammed 427 is a touch lower still, and he's quite happy.
Burning Brakes
Joined: Sep 2008
Posts: 753
Likes: 0
before going for the 427 ZL1 cammed 11:1 i have now , i had an L88 cammed 427 that at first ( iron heads closed chambers) was 12:1 and then i switched to 10:1 by open chamber alu heads. the CR reduction didn't made that big difference...meaning that low speed driveablility is poor anyway
with the comp cam ZL1 that's the same story : no TQ under 1800rpm , it idles at 1200rpm, exhausts stinks, horrible gas mileage 7mpg but... the throttle response is simply perfect for road racing and power is OK for that purpose.
So Richie ,go for the Zl1 cam if you really want to drive the car on a road course or you plan on driving fast on nice empty roads. otherwise go for a milder cam
Aldo
with the comp cam ZL1 that's the same story : no TQ under 1800rpm , it idles at 1200rpm, exhausts stinks, horrible gas mileage 7mpg but... the throttle response is simply perfect for road racing and power is OK for that purpose.
So Richie ,go for the Zl1 cam if you really want to drive the car on a road course or you plan on driving fast on nice empty roads. otherwise go for a milder cam
Aldo
Last edited by elle88; Aug 19, 2011 at 03:26 AM.
