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leaded gas?

Discussion in 'The Garage' started by cheyennesuper, Nov 11, 2004.

  1. cheyennesuper

    cheyennesuper Registered Member

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    My father tells me that the 350 in my '73 blazer might use leaded gas...Is this true?
     
  2. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    If it's stock and never been replaced or modified then yes.

    You may need to have hardened seats and valves installed, or run a lead substitute.

    Rene
     
  3. cheyennesuper

    cheyennesuper Registered Member

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    how can i tell if its already been modified?
     
  4. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Chevy engines have had hardened seats since 1972 , coincides with the change from gross to net horsepower , and also coincides with the compression drop across the entire gas engine lines .

    However , it would of been compatible with regular leaded since it has no cats . But since it has the right heads , just run unleaded since thats all you can get /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    We had a 77 Ford F-250 with a 400M. It did not have hardened seats or valves...apparently the first year for that was 78.

    I find it odd that chev would have done that 6 years earlier. Unless it was Kalifornia only.

    Rene
     
  6. diesel4me

    diesel4me 1 ton status Premium Member

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    It might be the cars and trucks sold in canada had different specs--we saw cars and trucks from the montreal area here often that still had points as late as 1980!!--and most of the chevy's from canada had no EGR valves or air pumps too,until many years after the U.S. versions did.
    As far as I know 1973 was the first year (in the U.S. anyway)they started using the "lightweight" heads with hardened seats in chevy's.Fords--who knows??--they seem to slap anything on some of their vehicles that will fit and work--a local steel building company bought a whole fleet of F350 2wd diesel crew cabs back in 1986--but nearly every time I sold a part to them for an 86 it didnt fit--most of the time we'd have to match up the parts,and it nearly always turned out to be 82,83,84,or 85 parts that fit--I think they built those trucks out of leftovers!. /forums/images/graemlins/screwy.gif
     
  7. Aquaman

    Aquaman 1/2 ton status

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    I run 100LL in my rig. Runs awesome w/ it, and it is perfect for a project that sits for long periods. It doesn't seperate, so there is no "gummage" /forums/images/graemlins/thumb.gif
     
  8. folkenheath

    folkenheath Worthless Trash Premium Member GMOTM Winner

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    [ QUOTE ]
    Chevy engines have had hardened seats since 1972 , coincides with the change from gross to net horsepower , and also coincides with the compression drop across the entire gas engine lines .

    However , it would of been compatible with regular leaded since it has no cats . But since it has the right heads , just run unleaded since thats all you can get /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif

    [/ QUOTE ]

    He is right, all of them had hardened seats from 1972 on. You can use unleaded no problem if the engine is original. In fact, some of the heads in 1971 had hardened seats as well, depending on how late in the year they were manufactured. You can run unleaded no problem. If you want to make sure of the head date and that they are original and not older, look under the valve covers and find the casting numbers and date codes on the heads. /forums/images/graemlins/smile.gif
     
  9. Emmettology 101

    Emmettology 101 3/4 ton status

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    I had the heads redone in my 82 Jimmy which had a 350 from a '75 K5. The heads that were on it didn't have the hardened seats.
     
  10. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Well seeing as how they were lightweight 1970's castings , they could of died , and the original owner replaced them prior to your ownership . 1975 was the first year of catylytic converters , and even though some trucks did not have them , they would have still made sure all the heads got the hardened seats for production purposes and to save money . Do you have said heads in your possesion ? Running numbers is easy /forums/images/graemlins/k5.gif /forums/images/graemlins/k5.gif
     
  11. Emmettology 101

    Emmettology 101 3/4 ton status

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    If that was directed at me. Unfortunately no. /forums/images/graemlins/frown.gif I sold my 82 around '96. Then bought it back from the guy in '98 and it had a different engine in it.
     
  12. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Well , you got your truck back , if it comes back its meant to be /forums/images/graemlins/thumb.gif
     
  13. Emmettology 101

    Emmettology 101 3/4 ton status

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    Ya, it was meatn to be... /forums/images/graemlins/thumb.gif I called the guy to see if he wanted to sell it and he had just been talking to his father abotu selling it the night before!! /forums/images/graemlins/smile.gif Unfortunately it's just sitting right now, but I still have it. /forums/images/graemlins/waytogo.gif
     
  14. cheyennesuper

    cheyennesuper Registered Member

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    well...the guy i bought the truck from said he was using unleaded so would the valves be shot by now if there is no hardened seats?
     
  15. rick88blaze

    rick88blaze 1/2 ton status

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    [ QUOTE ]
    My father tells me that the 350 in my '73 blazer might use leaded gas...Is this true?

    [/ QUOTE ]

    My '72 ran on unleaded gas. It never had any problems with it. it had the factory engine in it too. /forums/images/graemlins/thumb.gif

    Rick
     

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