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For those interested here are my test results for the Holley LS7 High Ram w/102mm TB
On my journey to 700+ RWHP for my NA LS7 I've actually tested 6 different intake manifold configurations in the ruthless pursuit of the magic numbers.....the OEM stock LS7 intake, Ported OEM LS7 intake, Beck Sheetmetal, MAST CNC aluminum LSX, Holley High Ram front opening and Holley High Ram top mount!
What's interesting is that there really are no surprises per se, just to recap:
......the ported OEM LS7 stock intake makes +13/0 RWHP/RWTQ more at peak than the stock manifold and I believe this would be similar to the Holley plastic LSx 102mm intake with a 90mm TB. Now with the 90mm TB on the Beck sheetmetal intake, the gains are is +21/4 RWHP/RWTQ over the stock LS7 intake set-up. The upper RPM HP gains made with a 102mm vs 90mm TB on the Beck intake vs stock OEM make a significant difference +42/4 RWHP/RWTQ!
Now here is where you have to have trust in the testing process and a little Algebra....the graph below demonstrates irrefutably that the ~$700 Holley High Ram basically performs about the same as my $2500 Beck Sheetmetal intake I wouldn't consider +2/4 RWHP/RWTQ as statistically significant when compared to that of the Beck's performance so I HOPE that we can all agree that the Holley and Beck really perform about the same and that this small of a difference is "noise level".
If we can agree on this much, then you can reverse engineer your way backwards to compare the Holley with the Ported OEM LS7 intakes and stock LS7 intakes using the data that I have provide above and the graphs below. Of course your have to use the 680 RWHP graph as the baseline for direct comparisons because the difference is, the 706 RWHP for the Holley is with Morgan heads vs Good heads so the only way to get back to apples is to remember that your can't compare the 706 RWHP Holley against the stock OEM LS7 intake with a 90mm ported TB and say hey, the Holley is good for +66/28 RWHP/RWTQ, it's only +42/4 but still I think that this is HUGE! And yes, you likely need a motor making the power level that I am to see similar gains so please don't go bolt the Holley on your stock LS7 and then be disappointed....this HP difference is representative for a max effort set-up! I hope this helps with your decision process when trying to downselect an intake manifold. And by the way, I will be selling both my Holley with the front mount, the extra top mount for it with fuel rails and the LSX intake shortly if anyone is interested once I figure out reasonable pricing. They have only been used on the dyno and a quick drive around the block.
Here is the Beck vs Holley:
I didn't talk about it much but here is where I tested the Holley with a flat top (tunnel ram style top) and mounted the TB on top vs the Holley front mount and Beck...as you can see no significant difference:
And lastly, the graph comparing the Holley to the Beck to the Ported OEM LS7 to the Stock LS7:
Nice info. Thanks for sharing. Quick question. ported ls7 vs ported fast ls7 102. 420+ cubes. street/strip 4th gen. which would you prefer. Thanks for ur input.
Nice info. Thanks for sharing. Quick question. ported ls7 vs ported fast ls7 102. 420+ cubes. street/strip 4th gen. which would you prefer. Thanks for ur input.
You bet! Personally I think I'd wait for the MSD intake before I broke my wallet out right now but if it was just between the ported LS7 OEM and FAST 102, the ported FAST has an edge since you can put a 102mm TB directly on it...now if you graft a 102mm TB flange onto a ported OEM LS7 intake it'd be a toss-up and the $$$/HP should drive the decision.
Great info provided John! You have saved many of us some $$$'s in testing what works and truly isn't worth the extra $/time for crazy custom parts on a big cube motor with well flowing heads.
I'm curious how the new MSD intake for LS7 heads works out! I know my AllPro LS7 single plane with a 4500 style TB and air filter is going to make my car look like a ProStock car for the hood I'll need... and not excited about that.
John B
Thank you for all the Invaluable data you have posted here, and in the other LONG Thread, you have saved countless 10s of thousands of dollars to
The members of this forum!
GNX7 Check out the new short race runners for the FAST 102
probably worth 35+ RWHP 6500-7500 in a 427-454 with big heads
and cam over standard runners, even shorter than MSD!
Probably lose 30-40 lb ft below 4000 rpm though.
Again, you're welcome guys...no sense in taking Trade Secrets to the grave....our Hobby has the perfect opportunity to flourish by informed decision making based on independent data and with Forums like this one, what a great place to share!
I LOVE that we have this community here. I own a couple other non-LS cars and I've gotten on forums for them and I'm beyond disappointed by how unhelpful those guys are when I have a problem. Wouldn't be surprised if most of them don't even change their own oil. Here we can pose the craziest mechanical/physics/chemistry question and someone will come along and answer it
Thanks a lot bro I was thinking about pulling the trigger on that new Holly hi ram I have a fast 102 but I think I'm going to wait on the new race runners for the fast intake I think that probably be the best fit for me
12-06-2014, 10:14 PM
For those interested here are my test results for the Holley LS7 High Ram w/102mm TB 
I wouldn't consider +2/4 RWHP/RWTQ as statistically significant when compared to that of the Beck's performance so I HOPE that we can all agree that the Holley and Beck really perform about the same and that this small of a difference is "noise level". 
