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225 V6 Engine Build, Piston Cr And Head Vol?

Discussion in 'Early CJ5 and CJ6 Tech' started by 1948Willys, Jun 24, 2020.

  1. 1948Willys

    1948Willys New Member

    I’m rebuilding my 1967-1974 Buick 225 V6 and can’t seem to find some information to help me on the build, if anyone has any insight or answers it would be greatly appreciated:


    I’ve read online stock compression height on the pistons is 1.87” but all the summit racing aftermarket pistons are 1.835” which would cut the stock compression ratio of 9.0:1 to 8.4:1. Question here is, is 1.87” truly stock? And if so does anyone make that same stock piston or even one with a higher CR?


    I also can’t seem to find any info on the stock heads, mainly looking for head volume to compute my CR.


    Build plan is going to be stock plus:

    -Headers

    -4bbl 390CFM carb

    -Slightly higher compression ratio (9.2-9.5)

    -A hotter cam to compliment all of that (research / math pending)


    I know the stock 225 heads are my limiting factor, it’s a budget rebuild and I’m just squeezing out as much HP as I can W/O dumping in a ton of money. I’m trying to reuse as much as I can.


    Thanks again for the help!
     
    1948Willys, Jun 24, 2020
    #1
  2. 73 cj5

    73 cj5 Not ready for the junkyard yet

    Did you check TA performance?
     
    73 cj5, Jun 24, 2020
    #2
  3. Keys5a

    Keys5a Sponsor

    The 225 pistons have a "dish" in the top. There are shallow dish and deep dish pistons which makes the two different compression ratios. The shallow dish are a bit harder to find. I don't have the two depth measurements handy. Sorry.
    -Donny
     
    Keys5a, Jun 24, 2020
    #3
  4. Warloch

    Warloch Did you say Flattie??? Staff Member

    If your wanting to do a lot with a V6 and looking at the options "V-6 Performance by Pat Ganahl" is the book you want to use for reference. It has what you will be looking for in it, including some good build options.

    You can get good used ones for about $38 on Amazon.
     
    Warloch, Jun 26, 2020
    #4
  5. Simi Valley CJ-5

    Simi Valley CJ-5 Chief Cook and Bottle Washer

    Have you seen this YouTube series yet?
     
    Simi Valley CJ-5, Jun 26, 2020
    #5
    1948Willys and Jw60 like this.