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 Emulsion change/ Hs Bleed change 
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Joined: Sat Jun 01, 2013 8:02 pm
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Revved Up wrote:
That is great news! Now, you can enjoy Drag Week!

My car is not nearly as fast as you. It weighs 3015lbs, 383sbc, 4.11 gears, TH350 with a brake, torque converter stalls at 5500. Typical 60' is 1.39-1.42, and best 1/8-mile is 6.57 at 103+. That is with nearly 6000ft DA, and typical DA at Barona is 4500-6000. So, I am sure it would fly at another track, just haven't been down the 1/4 in a while.

Your car is coming along great. It should be really consistent with everything you've been doing.

Good luck!



Thanks! Yes your car is moving well at that DA! This was with my slicks again YESTERDAY, But I think i'm finally on the right track! Removing that spacer freeing up travel was huge i believe
I'll be trying the radials on the next bracket race in july. I'll Have a log later on today of two runs with my meter to show afr too. So were still kinda on carbs here lol

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74 Firebird 3600 lbs
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Mon Jun 19, 2017 9:18 am
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So here's a couple of logs from sunday 3rd log i upped fuel pressure to 7, just to see if i could get that first part down, and its identical to run 2. Im beginning to think it has something to do with the car in the air and then coming down? I dunno I'm kinda lost on it, if i lean the jets the whole thing gets leaner, same with bigger high speed bleeds?


Attachments:
LM1Log 06-18-17 upped fuel pressure 7.log [38.14 KiB]
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74 Firebird 3600 lbs
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Mon Jun 19, 2017 6:31 pm
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Without going back 13 pages do you have a way to try different ignition curves, like a digital box? Understand that AFR is not affected just by the carbs fuel delivery but also by how the engine combusts fuel in any range of RPM or load. Misfires will change it, incorrect timing will change it, I've seen on the dyno when timing isn't optimized AFR can be all over the place.


Tue Jun 20, 2017 7:34 pm
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Mark I have a digital 6, so no way to try a different curve,I've got one spring removed on my msd so timing is all in basically at idle or just off it.I run 31 total right now, made peak on dyno at only 26? But it's slower at the track now with less timing, I'm running ngk 8's now, was running 7's when we built it n dynoed it, but carb also had skirted banjos too n 92 Holley jets with only a 1/2 spacer, running a tapered Wilson on top of that now with straight banjos and 16 hole blp boosters from 12.I just can't figure out y that first part has the hump like that, it's fine after I'm in high gear.

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74 Firebird 3600 lbs
9.95 @134.32 1.370 60 ft


Tue Jun 20, 2017 8:06 pm
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74 firebird461 wrote:
Mark I have a digital 6, so no way to try a different curve,I've got one spring removed on my msd so timing is all in basically at idle or just off it.I run 31 total right now, made peak on dyno at only 26? But it's slower at the track now with less timing, I'm running ngk 8's now, was running 7's when we built it n dynoed it, but carb also had skirted banjos too n 92 Holley jets with only a 1/2 spacer, running a tapered Wilson on top of that now with straight banjos and 16 hole blp boosters from 12.I just can't figure out y that first part has the hump like that, it's fine after I'm in high gear.


Where did you have it dynoed?


Wed Jun 21, 2017 3:42 am
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At my engine guys place, the only thing different also was he had a 6 al box, analog, but we started at 30, tried 32 made less and made more power at 26 so that's where we left it.

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74 Firebird 3600 lbs
9.95 @134.32 1.370 60 ft


Wed Jun 21, 2017 7:17 am
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Have you verified with your timing light and your in car box that your timing is actually what you think it is? I have seen timing vary 6* between dyno ignition boxes and the box in the car after installed.


Wed Jun 21, 2017 8:42 am
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74 firebird461 wrote:
At my engine guys place, the only thing different also was he had a 6 al box, analog, but we started at 30, tried 32 made less and made more power at 26 so that's where we left it.


A dyno is a "starting point" imo and gets ya close w/some basic info but the track has the final say. I'd also add more timing in small increments and watch the slip cos unless you have a bad ass efficient head or it's a "Poncho" thing, it may want more. My Dart liked 38 over 34 at the track on a given day but, lots of variables and also agree on a timing light check/comparison but as a mentor told me years ago," Never loan out your tire gauge, timing light or whatever
because no one treats em like you do AND, no matter what the numbers read, if the car goes quicker and faster then so be it". If your light is off and the timings really 34 but your light sez 27 then there's your number............... :thumbr:


Wed Jun 21, 2017 11:13 am
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Location: San Diego, CA
I agree.

I would try a fresh set of NGK plugs, make two passes, and see what the ground strap tells you for timing. I read the strap, along with mph on the timeslip. I increase timing until I see it near the bend on the strap, and watch the mph. When the mph stops increasing on the slip, roll the timing back to the setting that netted the highest mph, as long as the mark does not go beyond the bend in the strap.

I haven't dyno'd my combination, but I played with ignition timing from 28 to 39 degrees, and took a lot of notes. I jetted the carburetor for each setting, and have found that my small block does best overall at 36 degrees (it made more power at 39, but deadly consistent at 36).

I lost over 1mph and nearly a tenth in the 1/8-mile with the wrong timing.

Play with plug gaps, as well. Not to insult your intelligence, but remember that increased compression means less gap.


Wed Jun 21, 2017 11:30 am
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bigblockmark wrote:
Have you verified with your timing light and your in car box that your timing is actually what you think it is? I have seen timing vary 6* between dyno ignition boxes and the box in the car after installed.


How so Mark? I use a reg light, no dial and just read the marks on dampener? And yes these heads have a very efficient chamber make most power around 30-32 usually.
Last time I checked the ground strap it was in the middle, I'm at .035 now on plug gaps. I can check on another test day tho for sure. I'm heading back to the track sunday with the radials :). I measured last night and i have 6" of travel now up front with that spacer out. I called afco and they gave me a baseline from where im at now, and said to go full tight and back off 10 on ext and comp, Im already there on comp so i'll do that on the EXT side and see what happens, Its a race so i'll only get 3 time trials, I think with the new settings and the much needed travel I can get them to stick!

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74 Firebird 3600 lbs
9.95 @134.32 1.370 60 ft


Wed Jun 21, 2017 12:35 pm
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