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Discussion Starter #1
Has anyone went from a GT40 or similar style intake to a box R intake on a 306 with 6500 rpm limit? If so what did u gain? I just bought the Box R this morning to replace my GT40 and will have it on in the next week or so. Figured would see if anyone has done this already. If not guess I will be the first to share the experience!
 

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Please do share. Do you have any "before" data? Track times, dyno?
 

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Discussion Starter #3
Yes I have full setup details, dyno, track times, weight, u name it. I just got intake on this morning. Have a few things to finish up with the new fuel rail setup then will get to the track and share my results.
 

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Discussion Starter #4
Update: fitting

Got it installed, waiting on 2 AN fittings to come in so I can fire it up and drive it. First observation: looks badass. 2nd observation: does not clear 5.5" extended cowl hood when u use a 1" phenolic plenum spacer combined with a 2" egr delete spacer and when using an Anderson N/A power pipe as the inlet to 90mm throttle body. The 2" polished delete spacer looks super nice but not gonna be able to use it. Inlet pipe lacks a hair over an inch to clear the hood where edge of cowl is. Going to a 1/2" spacer should do the trick due to it being a lift off hood. A hood with a finished underside is not possible without spending $$ on drop motor mounts, K-member spacers, etc...
 

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Discussion Starter #8
No track times. Last weekend was US Nationals, this weekend we got rained out and next weekend is bracket finals. I chose a bad time to make a swap for testing lol. Around town i like it. Seems to Rev much quicker.
 

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Discussion Starter #9
Finally got to take this thing out and stretch it's legs. Rather than fall on its face at 5400ish it now pulls all the way to 61-6200. And with gt40 it was making right around 15psi but now right at 6000 it made less than 12lbs. So at the moment I would have to say makes more power and intake was huge restriction. I will however say car felt slower based on seat of the pants. Has to make more power due to higher rpm and less boost but hard to say. Going to track tomorrow so will have before and after track times. Intake/throttle body was only swap, same timing, same everything else. I was thinking about doing a dyno for people but I decided it wasn't worth the 150$. If someone wanted to pitch in I would but otherwise I wont.
 

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Discussion Starter #13
Test is done. Car was a total dog tonight. Best I could get was [email protected] 1.58 60ft. I even decided to throw race gas in it and added 6 degrees timing for 28 total. Nope still a turd. Very expensive failure. Luckily intake is what my new motor calls for
 

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Thanks for sharing your experience. What did it run before? If it makes you feel any better, I did some pain in the ass testing last night (dropping cat back at the track) with almost unmeasurable results.
 

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Discussion Starter #15
I thought I'd posted it. Car was running 6.60'[email protected] before. I changed intake and throttle body and I backed the rockers off just a fuzz. Not enough to kill anything. Took them from 1/4 turn back to 1/8. Those were only changes period Thu this test. Then spent 100$ on race gas hoping that cranking timing way up would offset how bad it died lol. Nope, basically spent 1400$ and lost .6 and 11mph lol. In my head I just don't see why, makes no sense. Shame I don't have someone close to me that could check everything over that's well experienced with valvetrain and what not. Maybe find something I am missing
 

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Discussion Starter #17
Pro Comp 210''s and custom cam. Cam was specd for gt40 intake with the rest of my setup. Complete setup is a few posts down titled "new personal best stock bottom end"
 

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Discussion Starter #19
I'm doing a ton of talking with some good people. I'm certain it's not the intake that killed it. I'm kinda in the thought of had something weird going on before but with the other intake it kinda hid it. With the much better flowing higher rpm intake it made what was kinda off instead seriously off.
 
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