Fat Head Requirements

Discussion in 'PSI Superchargers Tech Questions' started by Larry Wycoff, Feb 26, 2009.

  1. Larry Wycoff

    Larry Wycoff AA/GAS

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    I have an older short deck KB block and I would like to know if using fat heads is even a possibility? Do fat heads require spread bore lifters and a raised cam?
    Thanks for the help!
    Larry
     
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  2. suddenimpact201

    suddenimpact201 New Member

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    the lifter spread needs to be either 1.900 or 2.00. you have to do a little work to get to make the 1.900 to work. i think you just have to grind a little bit on the heads or the block. if it is the older 1.800 spread, i was told it wont work. hope this helps.

    joe
     
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  3. ta455

    ta455 Member

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    we did but it took some grinding for clearence on the block,but they probably made that 1.9 or 2.0 spread for a good reason so we are switching to a 2.00 bae now.
     
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  4. G Martin

    G Martin Member

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    I am also curious about this. I have a std deck TFX 96 block with 1.900 lifter bore spread, and have been thinking about switching from fuel to fat heads. I know the 2.000 bore spread is probably the best way to go, but not sure whether the 1.900 spread causes geometry problems and how much block / head modification it takes to get the push rods to clear. What about head studs, I have 9/16's right now.

    Thanks
     
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  5. Larry Wycoff

    Larry Wycoff AA/GAS

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    Thanks guys, good information. Unfortunately, the block is a 1.80 lifter bore.
    Given that my budget won’t allow me to purchase a new block, does anyone have any suggestions on type of heads that will work with this block and a blown alcohol combination, i.e. dart, aj muscle, indy so I can keep my eye out for a good used set to start out with?
    Thanks again!
     
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  6. afueldigger

    afueldigger tire wiper

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    Hello Larry You can make that combo work without grinding. Back in my 417 Donovan days we used to use off set lifters to get the spread we needed to clear the spread ports on the webster and mastodon heads I do not recall the part number or the offset we used but they are still available for the .904 lifters Im assuming your block does use the std .904 chrysler lifter.
    Hope this helps
    Gary
     
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  7. Larry Wycoff

    Larry Wycoff AA/GAS

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    Thanks Gary, great idea. There are two options for offset lifters (.904), oiling or non-oiling. Rookie question, do fatheads require oiling from the push rods?
    Thanks again,
    Larry
     
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  8. afueldigger

    afueldigger tire wiper

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    No you do not need oiling lifters there is no oil galley through the lifter bores
    in the block you are using....
    Gary
     
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  9. Larry Wycoff

    Larry Wycoff AA/GAS

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    Thanks Gary…I appreciate the help!
     
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