1/4 mi ET for given MPH

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Hot Metal said:
Unless you must run a DR why don't you bolt on a pair of 8.5x26" bias slicks, then its only messing with shocks perhaps and that snubber you mentioned to cure your 60ft issues, you can lean on the verter then and use all of what you have....you should then see those mid 12's.
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Thanks for the input. I may end up picking up a spare set of wheels and slick for trips to the track.

Hot Metal said:
I also think your carb is on the small side with that head/cam combo.
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You think? I have an old 850dp and a BIGS 950 sitting on the shelf. I couldn't imagine either one of those working very well on a mild 340, especially on a street car. I've been wrong before though.
 
mopowers said:
You think? I have an old 850dp and a BIGS 950 sitting on the shelf. I couldn't imagine either one of those working very well on a mild 340, especially on a street car. I've been wrong before though.
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All SBM motors like a big carb (factory 800 thermo) as long as they have some head/cam/gear/verter, they'll run stronger with a bigger carb. Sure small carbs run well, but most people seem to be fixated with the 750 size, re my post no.9, I went 2/10ths quicker at the track with a 4781 850DP over a 750DP, and thats still with stock unported 2.02 heads and probably only around 9.8:1. the 850 drove really well on the now limited street use plus we even fitted a 50cc front pump which made it noticeably stronger at the track on the hit and on the street....just gotta get a good tune in it.....that combo made an on track 366fwhp.
 
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When you bolt up slicks, better have a driveshaft loop. A l ot of places let you slide with DR's.

IIRC, faster than 11.49, even DR's need a loop.
 
With the cost of carburetors being what they are (having carbs to already choose from is a different story) wouldn't some drag radials, dialing in the current combo (jetting and timing) , and working on launch and shift points be a better plan than just running for a bigger carb? Smaller carb, bigger carb, you still gotta optimize things first. Seems the logical approach.
 
crackedback said:
When you bolt up slicks, better have a driveshaft loop. A l ot of places let you slide with DR's.

IIRC, faster than 11.49, even DR's need a loop.
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Around here faster then 11:50 supposed to have a roll bar too.
 
famous bob said:
Around here faster then 11:50 supposed to have a roll bar too.
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  • 11.49 - 10.00 needs a cage, up to date seat belts, snell 2005 helmet, SFI jacket, drive shaft loop, all minimum.
  • 9.99/6.49 or quicker need a license, motor diaper, chassis inspection.
  • at some point (not sure off the top of my head) your normal anti-freeze isn't allowed, have to use water wetter or something of the sort.
 
11.49 to 10.00 is roll bar....faster then 10.00 certified cage and all the other stuff
 
Not sure what a roll bar has to do with tire style/loop/ET comments. The time I posted was the point where a loop is required dependent on tire style. A slick requires a loop at his ET. A different tire does not equate to the need for a roll bar.

I know he is NOT putting a bar in the car from my conversations with him and has NO intent to run faster than 11.49.

Please continue with the hijack. :)
 
318willrun said:
Curious, are you allowed to run regular anti-freeze in you cars?
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That is track dependent (most tracks do not allow it)...but I would not for any racing, no matter how slow (or fast) your car is. Reason being, if you get a few drips of water under a tire, not too big of a deal, tires chirp, regain traction quickly...if you get a little antifreeze under a tire it is VERY slippery (like getting in oil) and could lead to an out of control situation more easily than water alone. Also, antifreeze is very difficult for the track to clean up without chemically (or physically) removing part of the race surface.

Also, 9.99/6.39 need licence and bla bla bla...
 
I have run 1.71 60’ on a f-70 redline bias ply tire. About 6” wide. 1” over arch rear leafs, rear bands cut off the leaf springs with kyb shocks. Stock 340 front torsion bars. A ptc 9.5 converter. No pinion snubber, 4:10 gear. Play with what you have learn it. Stay away from the water people drag out of the burn out box. The car will run 12.5
 

flyfish said:
That is track dependent (most tracks do not allow it)...but I would not for any racing, no matter how slow (or fast) your car is. Reason being, if you get a few drips of water under a tire, not too big of a deal, tires chirp, regain traction quickly...if you get a little antifreeze under a tire it is VERY slippery (like getting in oil) and could lead to an out of control situation more easily than water alone. Also, antifreeze is very difficult for the track to clean up without chemically (or physically) removing part of the race surface.

Also, 9.99/6.39 need licence and bla bla bla...
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For street cars at my local track, 3 things a must: dual return throttle springs; battery anchored; radiator overflow, its the first place they start. Then it's car by car, and equipment on it. 14 or slower that is pretty much it. 13's or quicker they want to see a helmet, and of course the faster the more required.
 
crackedback said:
Not sure what a roll bar has to do with tire style/loop/ET comments. The time I posted was the point where a loop is required dependent on tire style. A slick requires a loop at his ET. A different tire does not equate to the need for a roll bar.

I know he is NOT putting a bar in the car from my conversations with him and has NO intent to run faster than 11.49.

Please continue with the hijack. :)
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ALLRIGHTY THEN !
 
Ahh! These guys mean well. LOL ! Good info.

I think the ole Mopar suspension book, has 1/4 mile times, speed, and rpm, but nothing on 60'. IIRR So good question !
Seems like a 12 flat was @112mph, from that book.
I guess that's perfection.
 
As for tire pressure, spin the tires and look at or take picture of tire mark. You want even color all the way across. Light in the middle, bump up the pressure 2 lbs. check it again, light on the edges drop it 2 lbs. do this until you have even color across the tire mark. Another thing do very little burnout while out of the water. First hint of smoke you’re done. Most people over heat the tire. Drive around the water and back the rear tires in then roll out of the water and stop. Then do your burnout.
 
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