Announcement

Collapse
No announcement yet.

long tube headers

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #31
    I think I have traction figured out with the caltrax set up and 9".

    fred

    Comment


    • #32
      Fred, CalTrax are good - but without a front suspension set to "pop" up at launch most of the Caltrax benefit will be wasted. I see plenty of cars with all manner of traction bars spinning their wheels instead of moving out. These guys like to complain about poor track prep - meanwhile the well set up cars launch hard and post quick short times. The Ford 9" rear is overkill at your power level and wastes ~ 3% of your driveline efficiency vs. a GM 10 or 12 bolt or the Ford 8.8 differential. The GM "10 bolt" was made in 8.2" and 8.5" versions. At your power level even the 8.2" version would be fine, I've seen plenty of the 8.5" versions used reliably on 10 second cars. The Ford 9" has a less favorable pinion angle - but that pinion angle gives it strength (along with an extra pinion bearing) for the real high horsepower or power adder cars.

      From what I see of Prager's pictures, the angled back L79 Nova rams horn manifolds would be perfect.

      Thomas

      Comment


      • #33
        Thomas, what is your recomendations to make the front end pop, have used softer spring rates in the past but maby you have a better Idea also I set this rearend combo with future plan to step up to 6 to 700 hp. thanks.

        fred

        Comment


        • #34
          I used a Ford 8.8 with the 31 spline axles and 3.73 posi. I liked the way it fit a lot and it's lighter than the 9. 95 and newer explorer get you rear disks too. I cheaped out and got a 94 with drums but still a huge improvent over the Dana 27 brakes. I agree that getting power down is key. I'll look it up too but what's the caltrax and how does it work. On the next car I'm planning to go frame off and go four link but this car has to get done first. I still am interested in "talking" about fender well's and if anybody has them or an idea of what will fit.

          Comment


          • #35
            I know this does not answer your question but comes close.


            53K with 55-57 Chev. fender well headers, like they were made for it.





            63 T-cab with headers that were for a 73 K5 Blazer.Similar to the Larks but not quite.
            For getting the front end up at the drags I use the Moroso trick springs for 70-up Camaro and Firebird.

            Comment


            • #36
              As far as traction,I have Competition Engineering slapper bars that take the place of the lower u-bolt plate and are shortened so the snubber pushes on the spring eye. My rear end lifts at launch and pushes the differential down instead of the body squatting as the springs wrap up. Front end lift is minimal. I have NO wheel hop issues. You can see the Lark at launch in this video:
              http://www.youtube.com/watch?v=qIhiNQAtcDE
              It is not as up close as I would like but you can judge the front end rise and body attitude.
              The "traction bars" that just clamp over the leaf springs are for the boy racers in the Kmart auto center.The snubber hits on the spring pack behind the spring eye instead of the spring eye itself and when they do it just shocks the leaf spring and unloads the suspension aiding wheel spin instead of traction.

              Comment


              • #37
                Very cool I cant wait to do the same with mine, I dont know if you are familar with cal trax but a lot of guys use them with good results,They consist of a split mono leaf spring an adjustable ladder bar that goes from the bottom of the spring to rear end hosing moumting plate to an bellcrank that is located at the front spring eye and and 8 way adjustable rancho shocks beleve me when I say thay hook. if you are interested check out calvert racing suspensions there sight is full of cars standing on there rear bumpers.

                fred

                Comment


                • #38
                  Rickman has the scoop: the '95+ Ford Exploder has what most guys need in a hot rod differential.

                  Alan, the tri-5 fenderwell headers are a no go on a Lark - the engine placement is much too different.

                  Fred, whole books and longish technical articles have been written on drag suspension set up - check Jegs, Summit, Speedy Bill, and some of the drag suspension companies for more in depth reading. It is a two part symphony of traction and the rate of change in your engine rpm's. Anything that improves traction/loads the tires or spins your engine more rapidly is usually a winner.

                  Its a basic geometry and physics math modeling problem: what is the maximum available traction, and how do you get as close to that as possible over the length of the dragstrip. Since few of us have access to those kinds of answers we go about it a different way: we experiment around and see if the 60' times decrease or get longer.

                  Front suspension is one of the keys to getting the hook up. There are a couple of typical issues that should be checked:
                  1) Binding in any part of the full suspension travel.
                  2) Not having enough travel.

                  To check for binding/excess stiction you need to remove the springs and shocks and see how freely the suspension moves up and down. Often there is a restriction or mechanical conflict that does not allow full suspension travel. Fix as needed, and then select springs and shocks.

                  Drag friendly springs have a lower spring rate, combined with a taller uninstalled spring height - this creates more "stored spring energy", which is what helps the front end to "pop" up at launch. How much stored energy you need and the shock selection will change with the power level and all the other factors of gearing, clutch or torque converter setup etc. What you need now at the 350 hp level will NOT be the same at the 700 hp level. Some of the finest springs do not come from the mass merchandisers, this is where to go http://www.santhuffshocks.com/ Even if you think a spring is a spring, there really is a difference.

                  There is no easy way to give great advice in a forum reply, your best results will come from research and experimentation. A lot of guys try several different springs and shocks before settling on the best choice for their car. There are so many powertrain and suspension variables to consider. Generally at the 350 hp level you will want to be more aggressive on stored energy and rapid shock movement - but at the 700 hp level you'll need to back off or risk hitting the tires too hard and loosing traction.

                  Easy, no? Its also a set of compromises for what you can live with - how "drag" you want your car to be. A very well setup muscle car only needs ~ 575 hp to run deep into 10's - yet my '65 needs more than 100 more hp to run in the high 10's. Among the differences is my street friendly 3,200 rpm stall converter vs. a serious drag 5,600+ rpm stall torque converter.

                  I touched on the rate of change in engine rpm's, but that is a whole topic all on its own. In short: this is why most guys benefit from building an engine with the highest average horsepower over the rpm range between their stall rpms (or launch rpm for stick shift) and max rpms - rather than just building an engine for a higher peak hp number. Higher average power results in an engine that will more quickly wind through its rpm range. Its better to have a slightly lower peak, but higher average power. Higher average power will always lay down more total power over the length of the dragstrip - which is where killer e.t.'s come from.

                  Thomas

                  Comment

                  Working...
                  X