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Thread: 427 Windsor stroker?

  1. #1

    Lightbulb 427 Windsor stroker?

    I just got my Atomic setup to control timing and I must say that I'm impressed so far. My current timing curve is as follows. Total timing is 34°. Starts at 1100 RPM to full timing at 2500 RPM. 10° on the vacuum advance set to ported.
    The previous setup was MSD 8584 with mechanical set with a 28° bushing and silver springs and 12° of initial timing. With the Atomic controlling the timing as described I noticed an immediate increase in throttle response and power coming off of idle. What I did notice was it seemed a little flat and lazy when going to wide open throttle at around 60 MPH. My Thunderbird cruises around 1950 RPM at 60 and when it downshifts it starts pulling around 2700 and up. Car is a 1964 Thunderbird with an AOD behind the 427 and 3.50:1 rear gears. Should I add a little more total timing a few degrees, or raise the total timing RPM or both? I was thinking going to 38° total and 2800 on the RPM. Thoughts? Suggestions? Thanks, Ed
    Last edited by ak7an; 07-29-2020 at 10:02 PM.

  2. #2

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    I think your timing curve is too short. Maybe increase that, I think between 1100-3000/3200 RPM. Total timing with 34° is a good number. My engine doesn't like vacuum so I started the engine with 16°-18°, unported without vacuum add.

  3. #3

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    I did make some changes, I went to 2800 for the total and increased total to 38°. Backed off 2° on the vacuum advance. Haven't had the chance to test drive yet, but I'll see how these changes make the engine react. I had no pinging before, so that's why I decided to add a little more total. Thanks, Ed

  4. #4

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    After driving the car a bit I was getting a little bit of ping around 3000 RPM. Moved my total RPM to 3200 and changed over to non-ported on the vacuum advance. The engine is running really great with this setup. I haven't heard any ping and low end torque is good and really pulls hard from 1800 and up. The way I understand the non-ported is that would be like manifold vacuum, that's the way most vacuum advance works from the factory. Anyone know or care to explain the benefits of using ported advance? Thanks, Ed

  5. #5

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    I guess there's not much support for this forum. That's too bad because I haven't had any luck with getting help with MSD Tech support link on the website either. Take care, Ed

  6. #6

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    No support on this forum, especially from the MSD guys. It's sad! The vaccum advances works for low speed progression. 38° is too high. Make sure the final advance between 34-36°. Good to know your car is running great. Regards!

  7. #7

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    Thanks for the reply. I understand what manifold (non-ported) vacuum advance is for. Allows for more advance when there's no load on the engine, helps with economy and slow speed driving. Just would like to know what the benefits of ported would be? More performance on throttle tip-in than manifold? I guess I could try and compare low end performance each way and see if I can tell the difference. I can move my total back to 36°, I had read somewhere that a lot of the strokers liked 38° for total. Not had any issues with pinging at 38°. Take care, Ed

  8. #8
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    See posts #4 & #8: https://forums.holley.com/showthread...781#post218781 (Related Forum Thread)

  9. #9

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    Thanks Danny for the link. Very good info, and was along the lines of what I was thinking about manifold advance.

    Just to clarify on more total timing for a stroker. I believe it has to do with the increased piston speed, they like just a little more timing. Good stuff and fun to learn. Just wish the Atomic would datalog so one could see the whole timing picture. Cheers, Ed

  10. #10

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    Quote Originally Posted by Marchiori0912 View Post
    No support on this forum, especially from the MSD guys. It's sad! The vaccum advances works for low speed progression. 38° is too high. Make sure the final advance between 34-36°. Good to know your car is running great. Regards!
    No there's not! Not a bit and it's quite troubling. It honestly leads me to want to go to other products where I know I can get the answers and support I need.

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