FAST Beast

I also have pretty much the same build as yours. Iron 408, same pistons, PRC LS3 heads with hollow stem valves, FAST 102 intake, PTM 102mm tb, 50# FAST fuel injectors, racetronix pump with hotwire kit, 234-251,610-632-custom grind, marine lobe cam by Geoff Skinner, mine made 472-468 thru a M6 on the dyno. This cam i have installed now is actually the third i have tried with no better results than the first two. I am at a loss as to why it want make any more power, i have been over everything time and time again.

USMC5811

iTrader: (2)

whats your exhaust look like?

FAST Beast

Kooks 1&7/8 headers, Kooks y pipe into stock exhaust with a magnaflow but i have a electric cut out right behind the y

87silverbullet

iTrader: (11)

Ask Geoff Skinner why he chose that.

87silverbullet

iTrader: (11)

Because of internet hearsay. One person tells you to run alot of split for LS3 heads then the next guy tells you "why do you need a 17* split?"

All the vendors on here all have LS3 cams listed on their sites and they have as little as 6* of split up to the most I've seen is 20 something degrees. No one knows the right answer so that's why people leave it up to Geoff, patG, predatorZ, or the such. In this guy's case I don't think its the cam.

USMC5811

iTrader: (2)

i want to be the fisherman! so will someone explain to me what the 17* split is refering to. i understand all the numbers in the cam but havent heard the term "split" before

disc0monkey

iTrader: (10)

its the ratio of intake duration vs exhaust duration. generally these figures are tailored to flow rates of the intake tract and exhaust. so first you want to know your engine flows lets say X on the intake, and for this example 0.88X on the exhaust. then you want to figure how the gas density changes before and after combustion. then match your cam to that, that would make your cam match exactly what your engine needs. But it doesn't end there.


Then you can add more to the intake or exhaust to characterize the cam to your needs.


generally, excess in the intake side will give more torque early and excess in exhaust will carry the power band higher and if i remember correctly raise peak and average hp.

Sales@Tick

iTrader: (3)

Flow numbers mean literally nothing to me when selecting a camshaft profile and even more so in general. Flow numbers sell heads. I do not subscribe to the wide split theory with square ports in a N/A combination either.

I also can't wrap my head around(well I can, but I'm not going to bash others like some would do) why most of the dyno numbers in this thread for members 408's, are lower or equal to the stock stroke stock bottom end stuff we do at our shop. I have my results and theories, but they disagree with others who have posted in this thread. So as not to cause a food fight, I'll keep them to myself for now.