How to drag race your classic

Discussion in 'Classic Mustang Specific Tech' started by 10secgoal, Jul 22, 2005.

  1. If you are braking that much shi... stuff then you must be hooking really well :)
  2. Boy, glad I have an auto haha.
  3. Me too! I have stock springs with a leaf added, worn out shocks and no bars. Never a hint of wheel hop on street radials, slicks or drag radials. It has been 1.58 in 60' on the slicks and drag radials.

  4. Yep, yet another good lesson on drag racing your classic. If you are determined enough (or crazy enough :crazy:) to want to race hard using a manual transmission and sticky slicks--be prepared to break things because it will eventually happen. :)

    For me, the fun factor far outweighs the aggravation. I just try to build it better each time.
  5. If my car was a stick car when I got it, it would still have a stick. There is something about a manual trans in an old pony car. It just seems like old muscle/pony cars were intended to have 4 speeds.
  6. Wanted to bring this back to the top, since the season is here. :)

    1) Cutting the 6cyl springs was a bad idea. Gives more travel, but slows the rise of the front down too much. Still cutting good 60's because of more power, but it should be way faster. Probably fine to cut though until your getting into the 10's. Then they will start to hurt you cut IMO.

    I'm also adding the Calvert Strut rods, I can see how they will help. Should have some pics after this weekend.

    Last thing on my list is UCA and LCA. Mine are either orig or really really old. lol Gotta wait a while though on those, running out of fun funds.

    Pic of the strut rods

    Got new springs going in too.
  7. I didn't read through the whole thing but I will add this; when you get to the track uncap your headers. In some cases it can make a big enough difference.
  8. The thread that never dies...... I like it. Gets me back to look around and see what everyone is up to. I am still trying to figure out what to build next. Been very busy with getting ready for the kart racing season, I have one of my 6 year old twins racing and between that and work it leves no time for my racing/gearhead "hobby"
  9. Since this has been brought to the top again, I'll add a few more suspension findings that I learned from experimentation.

    Stick cars work best with a bias slick at the track. For a stick car that uses slicks, consider one with a stiff side wall. This keeps the side walls from breaking down so fast due to the hard hits and the slightly harder compound make the tread surface last longer. An example of this from MT is an ET Drag Slick-- 26x10x15S Unfortunately stiff walls are not available in every size but they are certainly worth the few extra bucks over a traditional bias slick.

    If you run Caltracs with a stick car, run the bar in the lower hole (softer hit) and add some preload. More preload also equals a softer hit. These suggestions can help lessen wheel spin off the line which allows you to try a higher launch RPM.

    This tip will work on any car--If you still can't get traction, try adding a 40-50lb bag of sand against the tail light panel. This action alone made a huge difference in how my car hooked. Cheap and easy to try. It can have its negative repercussions though as the added traction can also lead to increased parts breakage (in my case 2 tranny input shafts and a 31 spline differential in 3 consecutive weeks.) After properly beefing them up, I am very happy with the results and just may try another bag before the end of the year.

    With the above mods, my hard hitting 500hp 393w street stick car runs very consistent 1.57-1.63 60'ers week after week on our crappy, rarely prepped track. With further tuning I hope to get into the high 1.4 to low 1.5 second range this year.

    A mechanical throttle stop can add to the consistency of a run. Great for bracket racing if you can shift consistently. I also found it very useful when I got bounced for not having a roll bar (and rightly so.) I now dialed a 11.5 and with the stop in position I can be within a couple of hundredths of that each run.

    Roller front spring perch and a proper front end alignment will help keep the car from wandering on the upper end of the track. It should help transfer weight at the line, but in my case the car still hits too hard to see the benefit.
  10. ..some info on the CalTracks.

    No measures, but some facts/info about the idea behind Calverts design.

    Patent US5354092
  11. Thread bump.
  12. Wow, a flashback thread. Since I contributed previously, I guess its time for an update. Since my last post I've installed a 427w, a Jerico, mini-tubbed the rear and added 4.33 gears.

    I discovered that if you have a choice, a taller slick will generally give you a better contact patch than a wider one which equates to better traction off the line. Keep this in mind if you are filling your wheel well and must make the choice.

    The suspension is still pretty much the same as before. On the rear I have Calvert Mono springs, Calvert/Rancho single adjustable shocks, Caltracs in the bottom hole with zero preload. Rear shocks are set at "7" for the track and I adjust it to a softer "3" for the street. I now run a 28x10.5x15S stiff wall MT slick on 10" wide rims. This tire works far superior compared to the old 26x10x15's on 8" rims. The front front of the car is pretty much the same-6 cylinder springs, Calvert 90/10 shocks, and no sway bar. This combo has gotten me 1.46 60'ers with the fastest run being a [email protected]+mph on a good track. (3550lb race weight, with driver, full interior, roll bar, steel wheels, full tank of gas). I've found that launching at a higher RPM is helpful too as it keeps the motor in its power band-that is if you can stay hooked. In ideal conditions I've popped the clutch at 5700rpms. On my greasy home track I've had to drop down to 4900rpm's to launch consistently which is important when bracket racing. That keeps me in the 1.52-1.57 60's.

    Other improvements in traction came from adding a 39lb metal plate where the spare tire would be mounted in the trunk. The battery has been relocated to the trunk and sits on top of the metal plate. I no longer need to add any additional ballast in the trunk. A roll bar was installed and it helped to stiffen the chassis. During the mini-tub the front of the spring perches were welded directly to the rear torque boxes.

    The Dart block 427w is shackled because it still runs the AFR205 heads that were on the old 393w. The toploader became much more unreliable when I got it into the 10's and that led me to finding a used Jerico, which has been absolutely flawless over the last couple of years. I have stepped up to a slipper clutch for better launches off the line, plus they are easier on the drivetrain. The old 9" rearend housing was not braced and last year the tube flex caused the center section of the housing to crack. A truck housing was narrowed and braced across the back and on the underside for increased strength. Each time something breaks now, I try to make it better. Of course one could save more money in the long run by biting the bullet and doing it right the first time.

    I'm sure I have employed other things that help in drag racing and will add them as I think of them.

    Here are a couple of photos from the end of last year:



    Attached Files:

    #174 dennis112, Jul 22, 2015
    Last edited: Jul 22, 2015
  13. I should add that I have found out how important front end travel is needed to transfer weight. The photos in the above post were using my old 65' Mustang front end which had more than 5" of suspension travel. Last winters engine clearance mod led me to install a 68' Mustang front suspension. The new suspension only offers 4" of front end travel due to some factory design issues which causes the ball joints to bind which prevents full travel. Due to this (given everything else remained the same) I have had some serious traction issues this year at my home track even on the new MT slicks.

    After a long discussion with Opentracker, we believe that I can work around these issues by employing the Arning drop and then modifying the shock mount to allow for the added travel. Due to some additional bracing that I did when swapping the shock tower, this will require that I remove the motor to modify the area to let the drop happen. Also the 67-70 6 cylinder coil springs are both longer and stiffer than the shorter 65 6 banger springs which further complicates the front end movement.

    Since I am currently leading the points in 2 local race classes, any changes that need made will not happen until the track shuts down for the winter.
  14. I'd love to have a manual car, but instead I'm stuck with a 2 speed. :D