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Thread: Track times

  1. #41
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    That sounds easier and more accurate than measuring the clay on the piston when I put it together. I forget, what is considered a safe clearance?

    I have an order from Summit that is at about $70. (including the springs) Need something else to get the free shipping and a $10 off special.

  2. #42
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    Safe clearance on a street engine is .080-.100" on the intake, and .100-.120" on the exhaust. On a race engine with bushed lifter bores, accurate machining, etc. you can run as low as .055-.060" on the intake and .075-.080" on the exhaust. But you must check every valve/every piston and be diligent about valve springs. When everything is run this close, a new engine must have the heads removed after the first few dyno pulls or runs down the track to look for traces of anything hitting.

  3. #43
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    Last week I advanced the timing and finally (barely) got into the 7's, 7.981
    Today I backed off the timing a degree an got a 7.948
    Then I adjusted the Quadrajet air valve spring 1/4 turn TIGHTER and got a 7.815
    Gave it another 1/8 turn and it slowed down a bit.
    Best run
    ET 7.815
    MPH 86.93
    60' 1.724
    The Wallace racing calculators say 400HP and 406HP
    Weight was on the high side since I forgot about this weekend and had over 1/2 tank of fuel. So a little more than 3920lbs. I didn't allow for that in the calculations.

    Didn't stay for brackets. It's all tune and test for me.
    Tony

    1955 Bel Air Sport Coupe

  4. #44
    Registered Member 55mike's Avatar
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    FWIW, I have a close friend with a 55 sedan, stock ZZ502, OD-A/T, 3:55 gears, and he ran 8.6's .. so sounds like you have a stout street machine since it's in the 7's.. Just say'n..

  5. #45
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    Quote Originally Posted by 55mike View Post
    FWIW, I have a close friend with a 55 sedan, stock ZZ502, OD-A/T, 3:55 gears, and he ran 8.6's .. so sounds like you have a stout street machine since it's in the 7's.. Just say'n..
    Thanks. But for some dumb reason I'm about to spend some more money to make it faster. Looking at some aluminum heads with bigger valves. I'm still running stock heads.
    Tony

    1955 Bel Air Sport Coupe

  6. #46
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    There is still a ton to be gained with the 781s, I have seen several cars go high 6 low 7s in 1/8 with unported 781s with 2.19 /1.88 valves. I would ditch the hyd roller tractor cam first.

  7. #47
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    Quote Originally Posted by markm View Post
    There is still a ton to be gained with the 781s, I have seen several cars go high 6 low 7s in 1/8 with unported 781s with 2.19 /1.88 valves. I would ditch the hyd roller tractor cam first.
    Tractor cam? What would you suggest? Right now I have it shifting at 6K and I don't want to go higher. And it has to have decent street manners too, it's more of a street car than a race car. I'm already tired of the 10" converter on the street.

  8. #48
    Registered Member BamaNomad's Avatar
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    It's a long slippery slope building a street car to use as a competitive race car (or vice versa)... and the slope leads to a big hole that you can't see the bottom of... which is where all your $$ ended up!

  9. #49
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    Quote Originally Posted by 55 Tony View Post
    Tractor cam? What would you suggest? Right now I have it shifting at 6K and I don't want to go higher. And it has to have decent street manners too, it's more of a street car than a race car. I'm already tired of the 10" converter on the street.
    Ever try shifting at 5500, I have a complete .030 454 with 10-1 TRW forged pistons, .595/.621 Wolverine solid cam, Performer RPM intake, 800 Holley dp, 781 heads that ran 7.07 in a 3600 pound Camaro with a 4.10 Dana and a 10 inch TCI stalled TH400, it ran its best there.

    Ever wonder why I built this care see BamaNomads last post.

  10. #50
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    Making my Q-jet 1" spacer into an open spacer to sort of defeat the dual plane manifold, I ran 2 7.77's. Ran the calculators and got 400 and 407HP at the engine. Can't find my slip and forget what the 60' was. Not sure if I should cut a little out of the dual plane divider? The spacer stay on either way. My tires are about gone. Trying to find out if they guys at the track set some rules in stone for a 275 DOT tire class. I may get some radial slicks that are stamped DOT but say illegal for highway use. That doesn't make much sense but?? As radials I think I'd be OK on the street, just not in any rain since they have what is a joke for tread.
    Tony

    1955 Bel Air Sport Coupe

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