Drilled Angularity Hole Circle in Piston Head

Discussion in 'introduce yourself' started by 1968ChevyL79327/350, Aug 5, 2018.

  1. 1968ChevyL79327/350

    1968ChevyL79327/350 OBDLiterate(D)

    as an AVID FAN of Old School Cars, I’d read an article years back about Bill Jenkings running a 60’s Gen 1 327 Chevy that was dusting the Big Blocks like Crap through a Goose. I’d wondered exactly how many/diameter of, and at what Angle the Holes were drilled in those Forged 327 Pistons built by “Grumpy”that allowed Combustion Pressures being exerted behind the Top Compression Ring, reflecting in less lost HP (Blow-by) -by thrusting ignition pressures to be exerted on the upper Compression Ring.
    I believe in this Theory and am requesting that we can get this superior Modification
     
  2. Grumpy

    Grumpy The Grumpy Grease Monkey mechanical engineer. Staff Member

    first welcome too the web site!
    I think your referring to gas ports
    read these linked thread's


    http://garage.grumpysperformance.co...roove-depth-clearance-effects-ring-seal.5454/

    http://garage.grumpysperformance.com/index.php?threads/maximizing-piston-to-bore-ring-seal.3897/

    http://garage.grumpysperformance.co...g-and-installing-connecting-rods-pistons.247/

    http://garage.grumpysperformance.co...tion-of-crank-durring-short-blk-assembly.852/

    http://garage.grumpysperformance.co...ng-and-basic-piston-ring-info-youll-need.509/

    http://garage.grumpysperformance.co...piston-to-bore-clearance-on-your-block.14251/

    http://garage.grumpysperformance.com/index.php?threads/flex-hone.9538/#post-35100



    btw the main reason Grumpy jenkings vega was able to pull a few feet ahead of sox & martin and similar chrysler hemi cars, like dick landy, was a rule,
    that forced cars to weight a certain number of lbs per cubic inch, of engine displacement,
    at the time neither tire or suspension technology allowed anyone to transfer power to the pavement nearly as effectively as they can currently,
    and its a bit easier to accelerate a lighter car with a similar power to weight ratio.
    and the cars were running high 9 second times, something that is currently rather easily accomplished 50 years later ,
    (provided you have lots of cash to throw into the project of course),
    but at the time it was amazing to watch.
    BTW Jenkins also raced a camaro and if you watch the videos of the races in most cases the winner was rarely more than a 10th of a second faster.
    That was the time frame I grew up in and we watched those races with far more interest than the super bowl in the group I had as friends at the time.
    the SBC 331 (over bore 327) was impressive but as the races proceeded, the Chrysler hemi's and eventually the bbf engines,
    were eventually very competitive as suspension tech and drive train tech improved.

    The guys I raced were not all that concerned with rules, many of the cars at the time would run low 11 to high 9 second ETs,
    , but we were no where near legal, because most of us had larger displacements,lighter cars , or ran (questionable) fuel mixtures,
    or power adders like supper chargers, stack injection, or methanol alcohol,
    or tipped in a mix with nitro-methane
    one of my friends owned a vega that might have given Jenkins a decent race, but he was far from race certifiable,
    as he had a 393 hemi in the car, with a strait axle and the cars hood and trunk were fiberglass replica parts,
    (some of the first Id ever seen) the interior was completely gone,
    replaced with thin aluminum and a light aluminum drivers seat.
     
    Last edited: Aug 5, 2018
  3. Maniacmechanic1

    Maniacmechanic1 solid fixture here in the forum

    They ran ultra low gears in the Rear Differential too Grumpy.

    4.10, 4.30 , 4.56, 4.88 , 5.13, 5.38, 5.57, 5.86, 6.14.

    4.10, 4.30, 4.56, 4.88 Still practical today.

    Race car Trailer and a Tow Vehicle required for other than 4,10 & 4.30. Just barely Streetable.
     

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