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Thread: Help with new MSD system & 327 SBC.

  1. #1

    Default Help with new MSD system & 327 SBC.

    Hello! I'm currently chasing an issue with my 327 SBC.
    The setup:
    327 SBC - 0.030 with 10.5:1 pistons (don't actually know the true compression, but I know it is a little less due to cam overlap)
    Lunati Voodoo hydraulic cam & matching springs (268°/276° with 0.500" lift)
    Brodix IK180 heads
    RPM Air-Gap intake
    Holley Street Avenger 670 with vacuum secondaries

    Car had a Mallory HEI setup. Would get an occasional misfire at 6000 RPM, and I know the cam is good to 6500 so I decided to upgrade. Car ran AWESOME except for the occasional light misfire at really high RPM, but I knew the HEI I bought was only rated to 6000 RPM.

    A friend gave me a new in the box 8360 Pro-Billet distributor with the large cap added, and a new in the box 6420 6AL box. These are older parts, but they had NEVER been used.
    I bought MSD super conductor 8.5mm wires and the blaster high vibration coil.
    Auto Meter tach/shift light connected to the 6AL box output.

    Installed everything and it did not run too good. Traced it down on my own to plug gaps way too big. Installed new plugs with 0.035" gap and now I have an interesting issue.

    Car is incredible in first gear. It is a 63 Nova with TH350 trans, 3.42 gears, and ET street drag radials. Ran high 7's in the 1/8 with the Mallory setup. Now screams to 6500 with no issues in first gear. Shift to second, pulls hard to 5500 RPM and then misses/backfires like crazy.

    Car has NEVER had an issue with stalling. Has now stalled multiple times with this setup just randomly. Hard to restart after a stall.

    The distributor setup - I have one blue and one light silver spring on the weights. AS part of troubleshooting, I even replaced the weight pads to make sure they had not degraded while sitting in the box. I have the 21 degree stop in with 34 degrees of total timing (without vacuum advance). I have tested with the vacuum connected and disconnected. I have played with the timing +/- a couple of degrees, I have been on the phone with tech support 3 times. I am lost. I wish I had not sold my HEI, it would already be back in.

    So to recap the issue - runs awesome through first gear, falls on its face at 5500 RPM in second gear. Any ideas? Thanks!

  2. #2
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,581

    Default

    Can you do a rolling test in 2nd gear to high RPM to see how it goes? Sounds like you're blaming the ignition system when the carburetor, or fuel system is to blame. Gary
    Last edited by Gaz64; 01-15-2019 at 04:56 PM.
    Regards, Gary

  3. #3

    Default

    Hello Gary! Thanks for the reply! I have actually done 1st & 2nd gear rolling tests. Run up to 4000 RPM, hold throttle so it is “cruising”, and then run up the RPM.
    In first gear - screams up to 6500. In second gear - screams up to 5400-5500 and falls on its face. The only reason I'm leaning so hard toward the ignition is because this problem started when I changed from the Mallory HEI to this MSD setup. Ran MUCH better with the HEI. If you have anything else you want me to try, please let me know!!!

  4. #4

    Default

    If the ignition system is the cause of the issue, then it would either be the coil or the distributor. The 6AL either works or it doesn't.
    shake-n-bake

  5. #5

    Default

    Thanks for the feedback! After Gary’s reply, I talked to a tech at Holley who says he is VERY confident I have a bad fuel pump. Sending me a new warranty replacement. I’ll post the results & solution for others who read this thread! Thanks again!

  6. #6

    Default

    Awesome sounds good then.
    shake-n-bake

  7. #7

    Default

    Just wanted to make sure I posted the solution to the issue. Holley suggested a larger fuel pump. Went from a 110 GPH self regulated to a 130 GPH with an external regulator. No change. Rejetted carb up three sizes. No change. Ripped out all of the MSD ignition and replaced with a $79 Speedway Motors HEI. Car runs like a champ again. Not sure if I'm going to send the MSD in for testing or just throw it all in a box and put it in the attic for another day. Don’t want to spend any more money than I already have.

  8. #8
    Join Date
    Jan 2010
    Location
    Brisbane, Australia
    Posts
    1,581

    Default

    Sounds like it was a rotor phasing issue. Gary
    Regards, Gary

  9. #9

    Default

    Give us a call sir, when your with the car. That way we can go over everything just to make sure you don't have anything setup wrong. It could be something simple that's giving you this big headache.
    shake-n-bake

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