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r45tsx to long for my 305

Discussion in 'The Garage' started by the fall guy, Apr 1, 2005.

  1. the fall guy

    the fall guy Registered Member

    Jul 1, 2004
    Likes Received:
    Just wondering if a r45tsx plug would be to long for my 305 (85 k5) I know they are a little longer but are they too long. I heard a guy on this site run them on his sbc religiously but maybe he had a 350?
  2. diesel4me

    diesel4me 1 ton status Premium Member

    Jul 24, 2003
    Likes Received:
    might be a problem....

    They only used those "extended gap" plugs in 1975 only factory,to help reduce emissions and to take better advantage of the newly introduced HEI ignition system,with its higher voltage....many vehicles in cold climates had cold start problems with the extra wide gap plugs,they would flood easily and would not even fire until either new plugs were installed,or the vehicle was allowed to sit and "dry out" for several hours..my brother was a GM tech at a dealership then,he replaced hundreds of plugs when service bulletins were issued,and GM recommended the regular gap R45TS plugs gapped at .035-.045 in the place of the R45TSX plugs..

    It only improves idle and low end power slightly with the wider gap plugs--it can be a disadvantage at times,if the spark finds it easier to jump to ground elsewhere besides the spark plug electrodes while under compression,thats the path the spark will take--the path of least resistance...so any weakness in the wires,cap or rotor will be more noticable with the wide gap plugs..and they need a good coil with high voltage to fire them properly too,a task the stock GM coil isn't always up too...

    The R45TSX plugs MAY not work in all years or combinations of heads and blocks,its possible they might actually contact the piston if used in a motor someone changed heads on,like if they used 305 heads on a 350 as an example--I've always had good results with the R45TS plugs,or the "colder" R44T plugs in heavily loaded vehicles..no real need for the "wide gap" ones in my opinion.... :crazy:

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