302 XXX block

Discussion in 'Fox 5.0 Mustang Tech' started by stevesLX, Sep 17, 2007.

  1. So is there anything special about a XXX block VS a YYY block? Is one better than the other or is it just the same thing with differn't cating #'s?
     
  2. i thought XXX was roller and YYY is flat tappet, or the other way around...i asked this before(try using the search button), from what i know it has nothing to do with the strength of the block itself, so just pick the better candidate for the build based on measurements of the bore, and crank/rod journals, not to mention if the block is cracked, etc..

    ~Mark~
     
  3. XXX is a hydraulic roller block. Nothing special........
     
  4. what is a YYY?
     
  5. flat tappet i'd assume

    ~Mark~
     
  6. my block says yyy and its a roller.
     
  7. there is no difference between the blocks, except that one has XXX and they other has YYY
     
  8. +1

    The only difference is, it's more fun to say you have the infamous "porno" block! :D
     
    Cory natcher likes this.
  9. No way it's the Vin Diesel block...officially endorsed by the movie XXX. Or maybe it's a Straight Edge block and doesn't drink or do drugs :shrug:
     
  10. Just means its good up to XXX horsepower
     
  11. right, there is no difference. I think XXX is just an earlier roller block, like the one in my 85 stang, and YYY is newer, like my 91 block 347
     
  12. i didnt know you were on here
     
  13. if im not mistaken the xxx block was a non roller block. My block is from a 78 ford truck and it was a non roller before and it has the xxx on the webbing. I also believe they are a little stronger then the rollers as the webbing was a little thicker.
     
  14. my xxx block came out of a 5.0 exploder. definitely roller
     

  15. Mine's a XXX and an '85 which was the first year for roller blocks.
     
  16. xxx block here and a 91 roller
     
  17. Mine says ZZZ :shrug:
     
  18. I have a YYY block in my original 89 and have done an 88 and 92 original mustang roller blocks and they were XXX.Theres no rhyme or reason to them.
     
  19. Well I can't quote where I read it but I believe they are the same however the YYY blocks are believed to have a higher nickel content which allegedly makes them stronger......how much or how true I couldn't tell ya but I do recall reading it somewhere.

    My 86 had a xxx and the 331 I'm building is a yyy and they are both rollers.
     
  20. Best answer yet.

    The YYY blocks were cast in Mexico (they did something right), and the castings done there, are said to have a higher Nickel content, thus making them stronger. I'm not sure, and no one is sure on how much stronger, but I still wouldn't want to push more than 425 or so on any stock production type block.


    /thread