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do i have angled plug heads?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by shupach, Jan 28, 2003.

  1. shupach

    shupach 1/2 ton status

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    im looking at purchasing headers and i found a new set of flowtech long tube headers but holley claims they wont fit on angled plug heads, im puttin 305 headers on my 400(64cc) and i checked the casting number which says they're from 1980-1984 305's, does anyone know if these are angled plug and did i get a decent set of heads?

    phill
     
  2. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Do all your plugs exit at the same angle? If they do you have straight plug heads. I have 2.02 heads with angle plugs and cylinders 1,5,2, and 6 point a little down and toward the firewall, and cylinders 3,7,4, and 8 point a little down and toward the core support. Each set (i.e. 1/3, 5/7, 2/4, and 6/8 angle toward each other on angle plugged heads.

    I'm assuming yours are straight, and yes angle plugged heads are tougher to get headers for, but you can find them (even some of the ones that say they won't fit.....will).
     
  3. jmd

    jmd Registered Member

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    305 chambers have the wrong quench for a 4.00 bore, let alone the 4.125 bore of a 400. Get a different set of heads, lest you deal with detonation, poor combustion, etc. Seriously.

    And what he said. Yeah, the guy above me. I can't think of any 305 application angle plug heads. Hmmmm.
    matthew
     
  4. shupach

    shupach 1/2 ton status

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    its actually bored .030 over so the bore is 4.155 what do you mean by quench? while i was told they fit on all sbc's, people do say the wrong things, thanks for the advice,

    phill

    edit: i have larger valves on there something like 2.02/1.90
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Mortec lists the largest valve size on a 305 head as 1.94/1.50.

    rene
     
  6. Blazerfun

    Blazerfun Registered Member

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    If they are 305 heads, the largest valve would be 1.94 on the intake. Chevy to my knowledge never made angle plugged heads for the 305. Angle plug heads were made in the mid to late 60's and most of them had a 2.02 intake valve. If you have 202 heads the valves will be within 1/32" of touching and 1.94's will be about 1/4" inch from touching. The best thing to do is call a chevy dealer with your casting numbers and find out what you really have. 305 heads on a bored 400 will work, but the compression ratio and detonation would be through the roof. The motor would not live long nor run right. Some of the best heads for a "street" motor in a 4x4 are everyday 1.94 late model heads. The 2.02 while a great breather will cost you low end torque, they are made for rpm and without the compression ratio and a decent cam you out of the hole launch will be slow. Good luck on the motor, make sure you check those casting numbers!!
     
  7. shupach

    shupach 1/2 ton status

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    i just measured the valves and they are 2.02, and i have an aggressive cam, this is crazy stuff,

    phill
     
  8. Blazer1970

    Blazer1970 1/2 ton status

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    To answer your original question, those are not angle plug heads.
     
  9. shupach

    shupach 1/2 ton status

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    thank you

    phill
     

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