Max timing conventional head BBC.

Discussion in 'PSI Superchargers Tech Questions' started by Neil Morley, Oct 7, 2016.

  1. Neil Morley

    Neil Morley Member

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    Ive got a 555 ci BBC , new century aluminum block 10.6/1 cr. BMF 385 conventional heads 14/71 HH retro blower 39%OD makes 34 psi @ 8000 rpm, on Methonol what's the max safe timing do you think I can run?
     
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  2. Neil Morley

    Neil Morley Member

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    The ignition is an msd power grid.
     
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  3. SoDak

    SoDak Active Member

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    high 20's
     
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  4. BEDNAR1320

    BEDNAR1320 Member

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  5. craig moss

    craig moss Member

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    28max depending on how hot the ignition is. Plug gap of 18-19
     
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  6. Neil Morley

    Neil Morley Member

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    Thanks guys, I appreciate your help!
     
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  7. Bjs344

    Bjs344 Member

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    I run 30-31. Might go down to 29.5 if the water grains are really low. I Usually squish a bearing or two every 15 passes or so. I also have more compression. I don't recall the exact number but it's over 11:1. Short stroke, though, so the dome is decent sized which might require a little more timing.
     
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  8. 57Chev

    57Chev Member

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    I had a 509 Chev. I run mine with a Mag 44 and a crank trigger at 32 never had an issue. I try 28 and didn't have the power like 32 did.
     
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  9. Force Fed

    Force Fed Member

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    I run 33-34 deg. KB Olds (BBC) 557CI, R980 screw,40lbs @ 8000, 44 amp mag, AJPE heads.
     
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  10. Outlaw68

    Outlaw68 Member

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    I ran the same head on a 548 inch.. 12:1 motor before we went to the hemi. It ran the best @ 35* 14/71 HH K8 rotor. That head likes some timing.
     
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  11. Wildcatracing

    Wildcatracing Member

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    532 BBC 11.2:1 38psi boost, loves 32 with MSD10+ ignition
     
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  12. Torment

    Torment Member

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    I'm pretty low at 25deg, MSD 10+, VP M1, 20-22PSi with one of the new Whipple 8.3L screws... and low compression at 9.5:1 to boot. Rod bearings and pistons still look & measure like new after a summer of racing though:)
     
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  13. Blownalky

    Blownalky Top Sportsman

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    Look at he strap on the plug after testing, Mike Canter has a great article on that to get you in the right direction. These things are not Hemi's. I run my 526 BBC at 35 degrees on a PSI blown at 115over with up to 55 LBS boost at relatively normal moisture levels. It does depend on air, GOW and the compression and overdrive you have. The main thing is start out conservative and then move up. A little at a time. You need to know the altitude factor when you run or you are shooting in the dark when you run. This all assumes you have a MSD 10 or a MSD 44. Anything else at this level is wasting your time.
     
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  14. Neil Morley

    Neil Morley Member

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    Which head were you running on your 548 outlaw 68 before switching to a hemi
     
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