My 427 dyno, analyze this graph
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TECH Junkie
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From: Republic of Texas
Originally Posted by Viper
Over.
If they flowed 343@600 I doubt that was the peak. It's possible I suppose, but with those heads flowing that well at .600 I would bet that it carries further than that.
Originally Posted by btwarrior
Hello. I dont know alot of you here, but I do have some input on your rocker arm decision. The Comp Cams Pro Magnum Rockers are heavier...yes. But The extra weight is in the trunion area to decrease deflection. The valve spring itself doesn't see anymore weight than it would with a Harland Sharp. You wont see a difference in power or what you might think is valve float. The harland sharps will 'deflect' or bend more under higher spring pressures thank the comp pro mags. Your choice, but I wouldn't waste my money when you already have a better setup. About the oil consumption, block off all hoses to the intake from the crankcase. If it doesn't stop it is definately valve related. Some engine builders do not put valve seals on heads because of high lift and better lubrication. My Brodix came assembled, no seals on the exhaust. Smoked. Double check that. Thanks
Bravo, I'd look into the PSI spring kit that Katech is selling. It's a very light spring retainer combo that is showing very good results on their optron. Alot of springs we use have harmonics with our rough cam lobes, but these seem to be playing out. Use those, or see about getting a set of the "platinum" PRC springs that should be replacements for the ones you have now. Those 2.100 valves are heavy, and you need a good spring to control them. I think you've taken the "golds" to the limit.
Droping back to a 1.7 rocker should keep you well within the confins of those springs. Actual peak numbers aren't so bad, but I would be worried how "peaky" the whole curve appears. It should carry the curve from peak to 6800-7000 rpms nearly flat, but it tapers off pretty fast after 6000 rpms. Definitely not good, especially for a big cube motor. Does the cam have any advance ground in?
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TECH Junkie
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Well, I put some miles on it since saturday. Oil level is still good and I'm not noticing the smoke screen. Just a small puff of smoke on cold start up after sitting overnight. Even the rear bumper doesn't have black soot all over it like before and the gasoline smell isn't as bad. Hopefully all I have is a rocker issue now.
Check to see if the bottom of the retainer has smashed into the top of the seals.
Sometimes you need to cut down the tops of the guide for clearance, especially
with that high of lift.I have spun my combo to 7200 rpm with promags, morel liters ,
and patriot golds shimed tight, not with that heavy a valve or quite that much lift though.
Sometimes you need to cut down the tops of the guide for clearance, especially
with that high of lift.I have spun my combo to 7200 rpm with promags, morel liters ,
and patriot golds shimed tight, not with that heavy a valve or quite that much lift though.
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My 408 is doing the same thing as yours. I go flat at 5200rpms though. With the help of ET peformance on my heads, we figured out that I have the wrong springs. The new ones are coming and that should fix my problem. But your graph looks just like mine. Very flat and falls of around 6100rpms. Once that is fixed you will be good. I will have my new numbers this week. Good luck!
Originally Posted by 11 Bravo
Yup. Going back to stockers. Might even switch to a .600 max lift cam, too to be safe. The heads flowed 343@600cfm. The chart didn't go any higher so maybe that was the peak?
my 408 made 550rwhp with .293 @ .600 lift
fuel rail popped off, it didn't make it into the interior, but its bad enough. no fire extinguisher and it burned for about 5 minutes before the track crew even saw me 
btw, I had my heads redone with 2.08 valves and picked up to 310 flow at .600 and gained no hp. flow numbers up to .500 were the same
btw, I had my heads redone with 2.08 valves and picked up to 310 flow at .600 and gained no hp. flow numbers up to .500 were the same
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Originally Posted by 383ss
.600 numbers mean almost nothing. mid and low lift are what matters. what did they flow there?
lift intake exhaust
.100 70.2 59.3
.200 143.4 128.7
.300 216.8 188.7
.400 270.0 232.1
.500 311.9 257.2
.550 330.0 264.0
.600 343.8 268.0
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From: Republic of Texas
Originally Posted by BlkHwk
Have you been able to get your issue resolved yet?
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Originally Posted by beardWS6
My 408 is doing the same thing as yours. I go flat at 5200rpms though. With the help of ET peformance on my heads, we figured out that I have the wrong springs. The new ones are coming and that should fix my problem. But your graph looks just like mine. Very flat and falls of around 6100rpms. Once that is fixed you will be good. I will have my new numbers this week. Good luck!
