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#22 ·
FWIW and maybe nothing ..... I dyno'd collector sizing on my motor ......2" primary Stahl with slip fit collectors ...tried 3" 3 1/4 and 3 1/2 ....... on my BB 439/600hp pulled to 6800 max torque was up most with 3" max hp with 3 1/4 3 1/2 off only slightly to 3 1/4.... however the % increase of torque was higher than % hp improvement every time ....... I also tested a Stahl 3" split collector ..torque up &peak lower down but HP also fell more than straight 3" the split I understand is like the 4-2-1......... collectors were 13-15" long from transition cone ........ 3" are the longest

I wish I had tried collecor extensions



IMO your header size is not the first place to look ....... maybe try open headers
 
Discussion starter · #23 ·
here are some runs at the same track 10/29/2011 d/a 990-1500:

1.347-4.057-6.367@105.71-8.392-10.113@130.47---
1.457-4.062-6.380@105.61-8.412-10.136@130.21---
1.344-4.036-6.336@106.41-8.352-10.065@130.89---
1.437-4.151-6.454@106.36-8.470-10.180@131.04---deep staged, so knock a tenth off
1.557-4.135-6.442@106.08-8.463-10.179@130.85---also deep staged,

It is showing more power as far as mph goes and I felt like it was making more power thru the summer as it ran mostly in 6.4x's thru the summer, just missing something or something is holding it back but it isnt obvious as its not nosing over like a fuel system or ignition problem would do.
 
#24 ·
Harold Sutton said:
I disagree, my son's 481" ran about a tenth and two mph better with a ported vic. jr. vs. a Dart which was also ported. Best with the Dart intake was 10.15 and with the Vic. Jr. average times were 10.05-10.08 with a best of 9.98. All speeds were in the 133 mph range. This engine had Dart 335 CNC heads. I think the new AFR 290 CNC heads would give you a little more power upstairs.
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It's ok to disagree because I am not an experienced die grinder or flow bench expert. I just have faith in the guy who does my porting. He is smart as heck. His name is Roger Helgesen and is named in David Vizard's recent Port and Flow Test book. He hasn't steered me wrong yet.
 
#25 ·
Bob-Not that you would take my advice. lol Are you using the same shift points? Any chance you are using a different fluid in the trans to either tighten it up or loosen it up? I only mention because the first time out with my 5.3 (I know its a little different) I couldn't get over 100mph because I kept hitting the rev limiter in first gear. I short shifted the next pass or at least thought I did and it hit 116mph! We finally got the shift points at 6600 with a rev limiter of 6800. When I hit the shifts I ran 118mph, if I shifted a little earlier it would only hit around a 109mph. It was very significant. If I hit the rev limiter it just completely killed the pass.

Anyways, just a thought. It may not actually be related to the engine or any of those components at all. Still running some damn good times and very consistent.
 
Discussion starter · #26 ·
I'm not sure where the 1-2 shift is because its in the air, shift by sound which is what I do for a living driving a truck, shifting by sound. I shift the 2-3 at 6k by the tach, it doesnt have to go much above that to feel like its leveling out so I shift before that happens to keep it pulling, then it pulls fine to 7k as its picking up 25mph on the backhalf. I am using type F trans fluid since it was rebuilt a year ago June, had been running Mobil 1 synthetic before that. I am also running a heavier front tire, the MT sportsman front tires just to get some life out of them, front runners don't last long and wont hold up on the street. The Sportsman fronts were put on the car September a year ago. I was hoping for a match race this fall Delbert, maybe next year.
 
#27 ·
Bob West said:
I'm not sure where the 1-2 shift is because its in the air, shift by sound which is what I do for a living driving a truck, shifting by sound. I shift the 2-3 at 6k by the tach, it doesnt have to go much above that to feel like its leveling out so I shift before that happens to keep it pulling, then it pulls fine to 7k as its picking up 25mph on the backhalf. I am using type F trans fluid since it was rebuilt a year ago June, had been running Mobil 1 synthetic before that. I am also running a heavier front tire, the MT sportsman front tires just to get some life out of them, front runners don't last long and wont hold up on the street. The Sportsman fronts were put on the car September a year ago. I was hoping for a match race this fall Delbert, maybe next year.
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Because of my car's weight I also run those M/T Sportsman front tire's. While heavier in weight they are very stable on the big end with Bias Slick's.
 
#31 ·
Bob, does the car "freewheel" ok (no brake drag)? My brakes drag slightly when hot.
 
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#32 ·
We have found the MSD 7 boxes get lazy and we usually pick up .07 in the 1/8 when we get them repaired.:mad:We have tried alot of coils over the years also.In the 7 box we found the 8251 coil to be worth some.This is on my friends Superstocker and he tests everything at least twice,:yes:I just get to go testing and turn some wrenches for him.Here is a good site and interesting reading.Good luck

Kevin

http://techwestracing.com/
 
Discussion starter · #33 ·
69-CHVL said:
Bob, does the car "freewheel" ok (no brake drag)? My brakes drag slightly when hot.
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Yes it seems to roll okay, one of the tracks I run at has a slight downgrade from staging lanes to water box and if wheels are straight it will roll easily down this slight grade. I still have drums in the rear, wilwood brakes up front and they are not as tight as the oem discs I replaced.


Thanks for the website Kevin.
 
Discussion starter · #35 ·
It was showing fat on the dyno, we took quite a bit of jet out of it and still showed fat, there is a chassis dyno in town that is supposed to have a dyno day, not really interested in power but I am interested in AFR.
 
#36 ·
My business has me timing races (5k's, triathlons, cycling, etc....) on weekends so it was very tough to get out. My business is doing much better which is a good thing but doesn't allow me to hit the track as much. I only got to make about a dozen passes this whole year. I actually times two races in your area and wished I could have figured out a way to bring my car. lol Anyways, I am going to try and make it down that way next year at some point. Doing some minor body work and putting some 3.42's in the car right now. Should make it more enjoyable on the street.

If everything on your car is about the same I am going to guess a different size header will fix your problem. Must be choking it. Anyways, good luck.
 
#37 ·
What headers did Mark use on the dyno? Your's or his dyno headers?
 
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#38 ·
Bob, I have gone fastest with the current 3.5" xpipe and ultraflows. This is over open collectors, or 18"x3" collector extensions.....Hard to believe open 3" pipe hurt it that much but I would loose 2 mph going from open 3.5" collector to a 3" extension. The best thing I did was the 3.5" exhaust upgrade. Picked up torque and lowered 60ft, mph was same as open headers.
Carb is jetted 84/92, 38* timing.
 
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Discussion starter · #39 · (Edited)
o6r1man said:
What headers did Mark use on the dyno? Your's or his dyno headers?
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His dyno headers.

Garret is using 3.5" exhaust as well, maybe there is something to it. I was at 87/92 with 40* timing to get best results this year, my 6.32 which I ran last spring and once this fall and that is how it was jetted when it went 9.98 and 9.99 a few years back.
 
#40 ·
that is what I was getting at in our PMs Bob.
You might have to upgrade to see the improvements
 
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