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Bench race this - 125 mph 1/4, what's it take...

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  • Bench race this - 125 mph 1/4, what's it take...

    I'm gathering up some junk for a gutted 85 tbird drag car and gonna do a complete dirtbag cheapout on it, like that's new or something.

    Goal - 125 mph, let the ET goes wherever it goes

    I did a interweb calculator dealy and come up needing 425 hp for that. I'm also looking at 4.30's and 7000 on 1:1 on a 26" tire with a little wiggle room.

    Here's what I have:

    Gt40p's ported heavily, no numbers though
    1.75 tube 30" primary 3" collector headers
    302 - forged pistons, standard, 3cc "custom" valve relief, block is zero deck height.
    .041 x 4.10 gasket

    cam - ooops, 254 solid flat Crower, couldn't resist it new for 25.00

    Duration at .050"
    Intake: 254
    Exhaust: 254

    Intake: .337
    Exhaust: .337

    Parker Funnel Web (big single plane)
    750 DP

    it'll probably take nitrous, but if I can hit 2700 pounds completely gutted... thoughts?

    Davis DUI HEI

    C4 -3500 stall converter probably necessary if I don't go with a manual

    I have a lot of this crap already and looks like I can dirtball this in at 1500.00 +/- 250. It'd get the whole car in under 2500 and likely get me booted.
    Last edited by Beagle; January 5, 2012, 08:54 PM. Reason: forum ate my post. :(
    Flying south, with a flock of bird dogs.

  • #2
    Depending on traction, you'll be close...huge lift for those heads.


    • #3
      that engine will sound very nice.

      I don't know hp to .25 mile stuff...especially going a torque route with boxers and rigs.

      I never forgot the cams though. a little more duration, to heck with giant lift. I bet it runs along time too.
      Previously boxer3main
      the death rate and fairy tales cannot kill the nature left behind.


      • #4
        Roger that Bill. .539 is on the hairy edge I think. Worst case, I have a set of 1.52 roller tip Comp Chevy rockers and I'll convert it to stud and use them. Did I mention dirtball? The retainers say adds .090 to installed height and I hope I didn't read that backwards and that means I lost that much more. I'll have to do a wait and see I guess.
        Last edited by Beagle; January 5, 2012, 08:01 PM.
        Flying south, with a flock of bird dogs.


        • #5
          I ran 118 with NO Traction,tires spinning rear end out the whole way.85 Mustang 351w Alan Root Heads(I'm old) TREMEC with 4.11 rear on REAL street radials.The engine was a 69 block zero decked with the old 11:1 pop ups with the dome cut off,had a Performer RPM(I think) and 3310 Holley I cant remember the cam but it was a Motor Sport Solid,the biggest one in the catalog.

          I sold the car and the new owner put slicks on it and ran 10.80!!!! 126!


          • #6
            Doubt you need that much gear to achieve your trap speed objective.
            Last edited by mlcraven; January 5, 2012, 09:02 PM.
            Michael from Hampton Roads


            • #7
              buy any chevrolet


              • #8
                A friend of mine ran her 69 Camaro consistently 10.60's at 125 mph. You're gonna need a cage and stuff.

                Document every penny and take a bunch of pics.
                BS'er formally known as Rebeldryver

                Resident Instigator



                • #9
                  The chevelle has gone 10.96@124 .... but it needs more converter.
                  Whiskey for my men ... and beer for their horses!


                  • #10
                    Tbird - will take some gutting to get under 3000lb - but you can handle that - frame connectors?

                    Adjustable upper and lower arms? (tis a coil spring fox 8.8 yes?)

                    C clip eliminators? You'll need long studs for the axles and open end lug nuts to pass tech at those speeds I think.

                    Check the valve train geometry carefully when you assemble - you may need to use those 1.5 ratio rockers - or - even better - have the guides trimmed down a bit and run the 1.6. With that cam I'd feel more comfortable with threaded studs and guideplates anyway. That funnel web should mean the heads/cam are your RPM limiters - but I'm going to bet 7000 should not be an issue.

                    MSD will do the rpm limiting or does the Davis HEI have something built in?

                    I have an excel sheet you can use to predict trap speed rpm based on tire size and gear ratios (I'm sure similar are available on the net as well) Mine does not account for tire "squish and grow" which we all know happens with slicks.
                    There's always something new to learn.


                    • #11
                      Im thinking it is going to be difficult to get in the 10s with ported GT40 heads and only a 302, nitrous would help. If you over gear it you wont have anything after the 1/8th mark, especially if the heads wont pull where the cam and intake want to run. If I were trying that with a Ford it would be getting a stroker crank.


                      • #12
                        Yeah, big dose of Nitrous is the only way that combo will get into the 10's. Plus it's going to need to hook, and little slicks won't help much there. You'll need at minimum an 8 point roll bar or you'll be thrown out after a 10.99 pass. Actually, you need the roll bar after 11.49...


                        • #13
                          this whole deal started over some E6 ('86) forged Flat tops and went a bit out of control. It's an inside joke (really inside, like internal) with a dirtball 1000.00 engine budget to see if it will get anywhere close. The joke started when I bounced the daily off the rev limiter at 6600 and thought "Weak" ... wonder what it would sound like at 7000. Then it deteriorated to "I've never built a 7k capable V8", which then devolved to wondering what the trap speed would be at 7k with 4.30's and a 26" tire, which is about 125.

                          I figure on 200-maybe as much as 210 cfm on the intake, they're around 165 cc at this point but will have to measure to be sure. From everything I've looked at, E7te's, GT40(p), C9oe and D0oe all go around 200ish when ported half way decent. I don't know how close my junk will be to decently ported, or if that is enough volume / csa for what I'm asking from them.

                          I'm not worried about the ET - just the trap speed.
                          Last edited by Beagle; January 6, 2012, 10:16 AM.
                          Flying south, with a flock of bird dogs.


                          • #14
                            I just talked to a crankshaft guy - about $85 to clean and grind to 10/10 - add $200 to that if you want it balanced.

                            For your purpose - I'd have it balanced if you're going to use it long at 7000 + .

                            It will be fun as heck no matter what it ends up doing - and after all - that's the point right?

                            I looked at strokers too - pretty much adding $1000 to the price of a build even for the "cheap" SBF.... so - if you're goal is to use what you got - stick with 302 and see what you can do.
                            Last edited by milner351; January 6, 2012, 10:20 AM.
                            There's always something new to learn.


                            • #15
                              John = yep, that is the idea. The crank looks good enough to me as is, hell I may even re-use the bearings. It's a single purpose experiment, just for fun. I don't expect it to last long and won't cry if it windows itself. The long block was a 75.00 ebay purchase, complete with Edelbrock Performer 289 manifold (no egr) worth maybe 50.00.

                              The E6 pistons were from another engine that got a stroker kit, they are the kind of piston that gets given away or melted because they don't have valve reliefs in them and as BBR mentioned, you can put E7's in for nothing. I'm counting their cost as Aluminum weight at .45 / pound.

                              The most expensive part of this whole thing is springs/retainers/lifters @ 300.00
                              Last edited by Beagle; January 6, 2012, 11:15 AM.
                              Flying south, with a flock of bird dogs.