351M build

Discussion in 'General Ranchero Help' started by Matt Winters, May 13, 2021.

  1. Matt Winters

    Matt Winters In Second Gear

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    Alrighty, gentlemen. The 351M is nearly ready to be pulled. Considerations are to be made. I am thinking of putting a Edelbrock 1906; which is a spread bore 650CFM mechanical secondary carb. That will be paired up with an edelbrock performer intake. I am considering a Thumpyr cam from Comp Cams. My concern here is the idle vacuum will be too low for my AC and power breaks. Thoughts? Recommended headers?
     
  2. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    The A/C controls vacuum will be a problem, but for power brakes, you can swap to hydroboost, or that self-contained hydraulic power booster (I forget the name).
     
  3. Matt Winters

    Matt Winters In Second Gear

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  4. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    You might want to ask that as a separate question, rather than as part of posting my quote.
     
  5. Matt Winters

    Matt Winters In Second Gear

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    Oops. My bad. 650 Mechanical Secondary should be fine I think. It has a 4.56 rear end, so it should be able to spin up pretty fast.
     
  6. Hillbilly

    Hillbilly In Maximum Overdrive

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    I have seen some rather simple cures for ensuring enough vacuum storage for the a/c and heat controls. Simply "T" into the hose going to the storage canister and add another storage can. Just make sure your "T" is in the line behind the vacuum check valve, not on the engine side of the check valve. A few blips of the throttle after start up should provide enough vacuum to keep the climate system happy. A big cam engine might produce little vacuum at idle or on acceleration but as the engine coasts back down from some rpm it will make enough vacuum to work things if you have ample storage.
     
  7. Matt Winters

    Matt Winters In Second Gear

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    Thank you for the info!
     
  8. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    So, instead of one #10 soup can, you have two...No soup for you!
     
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  9. rocco611

    rocco611 In First Gear

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    the 351M engine is a low compression engine if still in stock form , find out the dynamic compression you need for the cam you choose. a big cam with low compression pistons will not perform well. you may want to change to a different piston and or cylinder heads.
     

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