what ya think 11.39:1 and AFR 205s

what would the DRC be it it ground with any advance or anything

i want bottom im thinkin either would work in my application

 

A T-Rex has a 242 intake lobe on a 108 icl, so it has 2 degrees of advance (110LSA) I come up w/ a 8.47 DCR w/ your 402 setup. I put this cam in my LS7 but on a 106 icl. That would put your DCR at 8.62.

 

yep thats what i come up with also. 8.47 and wow the 2* more for a 106 would make liker low end.

 

it would also die off a lot faster after peak HP. more advance for a higher dcr/ better low end, doesn't come for free. it won't carry far, it would be peakier.

 

Mine carried to 6700/6800 before heading south, so w/ a Fast manifold that typically peaks around 6300, the 106icl would be fine.

 

word!

 

how does that bad boy feel ? thats the question

 

I agree, most stroker motors like a tighter LSA. A common rule of thumb when going from a 350 to a 383 when all other things are held constant; tests have shown that a tighter LSA will benefit the extra cubes. Speaking from my experiences in the past with GEN 1 stuff. I see no reason why this logic would not work on a LSx based engine. Relatively similar valve sizes and bore size.
The more cubes the intake has to feed the earlier it has to open. If it is relying on any exhaust scavenging, the exhaust valve must be closed later.
This means that for a given set of heads (AFR 205), a big-inch motor requires more overlap to produce optimal results. Hence why some AFR 205/346 perform well with 112 LCA, yet the 402/408's like the 108-110 LCAs
From my experiences power falls off much faster on the too wide side compared to the too tight side when dealing with LCA.

It has been learned by some builders that the valve overlap period has more to do with the success of the induction stroke than any other factor. If the intake charge does not get going in the first half of the event, nothing will make it up in the second half.

Using valve overlap for cylinder filling encompasses what many believe to be the 'fifth' cycle to our four cycle race engines. The right valve overlap and timing coupled with a tuned header creates a scavenging effect brought about by negative pressure created in the exhaust which has a much stronger draw on the intake port than the pressure differential created by the piston going down in the bore. This is how normally aspirated engines can generate VE (Volumetric Efficiency) numbers over 100% on an engine dyno. My Gen 1 406 SBC drag motor with a Track 1 head and 1080 Dominator/ Super Victor intake had VE numbers at the higher RPM scale of 118-120% out of a normally aspirated, non-boosted engine. Very common to see this in race engines. How does this happen? Answer: The FIFTH cycle.

Opening the intake valve earlier in the event will promote good cylinder fill. Couple this with a high velocity good flowing small port head (AFR 205) and you can actually have better cylinder fill than with a large port head if everything else is right.

"Quote - One fact that all my cam testing has indicated is the starting point for any cam spec should be the LCA." - David Vizard

Of course there are other things to consider which have been proven by the success stories in this site such as the proper IVC points for the manifold/head combo and CID being used, proper ICL install based on what the ultimate goals are, etc.

So many other cam reads I have seen on this site focus primarily in the IVC event, a BIG part for DCR, but there is more to the puzzle........

BTW, VE (Volumetric Efficiency) will play a devil's hand in the DCR number which is really an indicator of low engine speed behavior, throttle response, etc. At high RPM, specifically the torque peak and beyond, the benefit of the 'fifth' cycle and the potential for VE's better than 100% are in play. At this point, the engine experiences the FULL stroke length and the nominal swept cylinder volume is compressed at the SCR, or even higher regardless of the intake closing point.