Lifter bore reinforcement

Discussion in 'Small Block Tech' started by Mark Demko, Feb 15, 2020.

  1. Mark Demko

    Mark Demko Well-Known Member

    I know TA makes it for the 455 because of the lightweight casting of the block, and high spring pressures aggravate the thin lifter bores, but do you machinists, engine builders, and racers think this will be an issue for the 350?
    At what point does this become an issue?
    Im thinking for street and occasional track use with moderate spring pressures..... 350 or less over the nose, its not an issue???
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    I am at 370/145 with no reinforcement.:)
  3. Mark Demko

    Mark Demko Well-Known Member

    Thanks Larry, that answers my question, Jim Weise built your current engine, yes?
    If so, and he didn't think one was needed, that's good enough for me:cool:
  4. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Bill Mah was using a huge roller cam in the 1021 HP engine and he didn’t have any issues with the lifter bores.
    Mark Demko likes this.
  5. Mark Demko

    Mark Demko Well-Known Member

    I was just curious if there are any structural differences in the casting around the lifter bores between the 455, and the 350.
    I know there are FAR fewer 350's with rollers than 455's, and 455's see WAY more track duty, than the 350.
    The '86 '87 Turbo V6 is super beefy in that area, and there's tons of rollers in those engines by now, I've never seen a lifter bore girdle for those nor have I ever heard of any issues.
    Its me thinking again if the lifter bore breakage on the 455 was a few isolated engines that were pushed WAAAAY past their design limits and a roller with realistic spring pressure is fine in a 455 or 350;)
  6. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Yes it’s a good question
  7. No Lift

    No Lift Platinum Level Contributor

    400 over the nose is where you have to think about it in a 455 and that would probably only be with a solid roller of noteworthy size. IIRC the 350 has less of an open area in the valley between the lifters compared to the 455 and because of that I would think it is stronger in the lifter area.
    Mark Demko likes this.
  8. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    I don’t remember the “on the nose” pressure but here were the specs:

    Motor Breakdown:
    350 buick stock 2 bolt main block 3.830 bore x 3.85 stroke (stock configuration) All ARP Studs throughout-60-80psi oil pressure running 50w Redline stock oil pump.
    Eagle crank, Childs & Albert rods, J&E Pistons 8.5 comp
    Custom Comp Roller Cam-246/260@.50 .578/.600 112LC installed straight up.
    850 CSU Carb and Hat 80/88 jetting on final pull
    Aeromotive A1000 regulator
    Race air-to-air intercooler w/ a 125 mph fresh air fan in front.
    Headers are 2" tubes - 21" long - 4-2-1 merge into 3.5" x 4.5" megaphone 5" long.
    Port IRON BUICK HEADS 290intake/200exhaust 1.6 Roller Rockers
    Cometic gaskets
    Ported STOCK IRON 4BBL INTAKE with plenium milled out
    5" carb spacer

    2 different ATI superchargers were used:
    D1 Procharger
    F-1 Procharger- Chevy cog adaption. Drive: 8" & 6.75" Blower: 3.5" down to 2" in 1/4" increments. 8" and 3" were the most used up to 16psi.

    Motor, N/A Hp and torque numbers were mid 5's NA and the graph pretty much went flat just over 5800.

    First Combination D-1:
    838.5 hp @ 7100
    674 tq @ 6000
    12 psi.

    Boost to 15psi (overspinning blower)
    881.1hp @ 6950
    711.1tqe @ 6105

    Second combination F-1C:

    950 hp/ 731 trq. Ran it up to 7200rpm on PUMP GAS!! 20psi
    upper 900's with more tuning on following pulls......

    on the seventh and final pull w/race gas and 20psi:
    1021 hp @ 6800
    808 ft. lbs. trq. @ 5750!!!

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