first trip to the track

Old 07-11-2007, 02:46 PM
  #1  
firestone
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Default first trip to the track

Hello, I took my car to the track for the first time and although it ran a little slower than I though it would, I am pretty happy with it. I just wondered if you guys had any idea what difference cutouts and 4.10 gears would make. The carb was giving me some trouble to the point where it loaded up so bad that the motor actually shut off a couple of times while shifting into second gear. I have a 1000 cfm pro systems carb that is getting rebuilt for the street as we speak that should work a little better. Below is my current setup

Car:
1972 ventura (probably around 3500 lbs with driver)

Motor:
496
9.5:1 compression
950 willies carb
ported 2.19 1.88 valve 049 heads
port matched victor jr intake
248 254 @.050 .600 lift solid flat tappet cam
pro magnum roller rockers...

Exhaust:
2 1/8th inch Super comps
2.5" exhaust out the back with flow master 40 series mufflers

Tranny:
Turbo 400
3000 stall

Rear end:
12 bolt posi
3.55 gears
cal tracks
Hoosier QTP's

The car hooked just fine, but obviously struggled off the line due to the gears.

On the runs that went well, it did not stumble anywhere in the run.

60 ft's were right around 1.9 for all runs

Best 1/8th mile time was 7.98 at 90 MPH

With gears and open exhaust I was hoping for something in the 7.3 to 7.4 range. Do you think that 4.11 gears and open exhaust could get me there? What do you think the effect would be?

Thanks a lot
Adam
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Old 07-11-2007, 04:02 PM
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bjuice
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making up a 1/2 second is a bunch..however your at the e/t range to where you can lower e/t's rather easleiy and quickly with the right adjustments..its not unitl you reach the 6.50 mark until it starts to cost and harder to lower your et's...

i would say open exhaust you could count on 1 tenth on your car...if you get more then great..if you come in a little less do not be surprised..

the gear will make a huge difference...what was you turning thru the lights with your 355 gear ?...this will tell us more on what the gear will make up..

normally when a carb loads up its when your off the throttle...when your throttle is wide open is should keep it cleared out...be sure to check your fuel pressure and make sure your not running out of fuel...lets us know.


ohhh by the way...GREAT ET'S AND MPH YOUR 1ST TIME OUT...and the car is on the heavy side also....
You are till spinning a good bit....cause 90 mph should have you in the 7.60- low 7.70 range

thanks Brian
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Old 07-11-2007, 11:07 PM
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cepx111
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First thing I would do is the things that dont cost like uncapping your exhaust it will help allot. Like bjuice was saying in his reply your mph is high for a 790 et sounds like its spinning out of the hole, so look into possible traction issues, play around with the air pressure on the rear tires, I would start low like 10 then go up till it starts spinning, you want to run as much as you can for the higher mph and stablitiy on the big end. Do a harder burn out or less of a burn out and see what makes the car hook better. Play around with your shift points too to see what helps and what doesnt . Also if your running a front sway bar take it off, it is of no use at the track and henders weight transfer. Next thing I would do is get a taller gear, it will help you out tremdously, I would personally go with a 488 or 513 if your not planning on doing any 1/4 runs the taller gear will get it moving quickly off the line, a small gain on the small time means a big gain on the big time. A higher stall converter will help a bunch too, my old camaro picked up a full half second when I went from a 10 inch 3000 to a 8 inch 5500.
Are you deep staging? deep staging will slow your et' by a couple of tenths. Personally I like the shallow stage technic, I roll into the first beam and then stall up some and inch in till I just barley turn the second light on, that way I know excactly where I am and I have a good running start at the sixty foot light. this wil help you be more consistent on the light and allot more consistent on your et's. Then you can adjust the way you react to the tree, then fine tune with adjusting air pressure in the front tires.( higher pressure helps cut better lights lowering it slows down your light ) Personally I run between 50 to 60 psi make adjustments accordingly at the track, but I wouldn't recomend going over 60psi.
The heads seem small for that big a motor too, you might want to consider getting some bigger heads or getting your intake seats cut out for a 2.25 vavles along with a bowl hog job to unshroud the bigger valves. Also higher compression and a solid roller would wake that thing up big time, basically where your at with your bbc, you are just scratching the surface, there is allot more potential there. Goodluck and keep us updated, Charles
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Old 07-12-2007, 09:53 AM
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firestone
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When the car ran a 7.98 @ 90 mph, it spun maybe a quarter turn. My brother and some friends were watching and they were keeping an eye on the tires on every run. Traction did not seem to be an issue. I have the Hoosier Quick Time Pro's wtih the big Hoosier lettering on the side, so it is easy to see if they are spinning or not. I was running 20 psi in the rear tires, 35 in the front and I have mulit leaf springs with cal tracks. The tires are 28 tall and 10 inch tread.

The car never gets into third gear in the 1/8th. It is running ~5900 RPM at the end of the 1/8th in second gear.

I am shallow staging exactly the same method you explained

I probably will not get new heads for a long time. These ones have significant porting. I wanted them since the car is street/strip and I am running a somewhat mild cam.

One other thing; sometimes, when I let off the gas on my burnout, it would die. When I restarted it, it would puff black smoke for a second. There was a correlation to the car dieing after the burnout and having trouble when it was shifted into second.

Thanks a lot for the replys

Adam
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Old 07-12-2007, 10:45 AM
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chevysb400
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once you get everything worked out on it, put you a shot of nitrous on it, then it will really get down in the numbers
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Old 07-12-2007, 09:24 PM
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cepx111
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It's always good to have friends watching you at the starting line that's a big help. Not really sure about the carb problem sounds like it might be a high float level or too high fuel pressure, but you also indicated you might be switching carbs so that might fix itself.
If your only going thru the traps in second gear it definetly needs more gear as a turbo 400 already has a short first gear anyway, so a taller gear would be a big diffrernce but like I said your gonna want a little taller gear than a 411 because if you dont you'll be caught up in a shift just before the finish line which sucks, you wanna be firmly in third before then which is same problem I had in my old nova, it had a t 400 with a 411 gear and I was always shifting just prior to reaching the finish line, I ended up putting a 488 in it and it was almost perfect not to mention it picked up my et's too.
Also I'm a big fan of "most bang for your buck" and nitrous used at lower levels can be a safe and affordable way to make significant gains in et's real quick. You can score a adjustable entry level kit for about 300 to 400 bucks, and with a 125 to 150 horse setting you can expect about a half second gain in your car.
Goodluck, Charles
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Old 07-13-2007, 04:52 AM
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spib
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I have hoosier quick time pros, and e-mailed hoosier for recomended air pressure they said start at 12-14lbs, I went down to 10lbs felt very good on being stable. Jeff or MM with the bad ass chevy II runs 8lbs in his hoosiers, 20lbs seems high, for that slick, I ran dot bfgoodrich radials at 20lbs, to me sounds like to much air in slick.
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Old 07-13-2007, 05:17 PM
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I run 10psi in my 29 x 10 hoosiers. Far as the carb goes check float level, fuel pressure (about 7-8 psi), be sure it has a slosh tube front and rear, I've seen some builders leave rear out and it causes problems when your on the brakes after a burnout. Definately more gear will help a bunch, 430 or 456 and still allow you to run 1/4 tracks. When you open the headers you may find it necessary to go up on the jets a bit. Also when you stall the converter don't try to stall it 3000 at the tree. maybe just 1500 or 2000 anf allow it to flash the additional 1500 or 1000. Once you learn to stage this way, you'll have beter reaction and 60 ft. times. Doing this allows the suspension to work instead of being in a preloaded state.
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Old 07-14-2007, 08:14 AM
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firestone
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Thanks for all the replys. I am getting the carb back on monday. It will be interesting to see how that effects it.

Adam
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