How Much to Mill Heads? 73 Heads on 71 Block?

Discussion in 'Small Block Tech' started by knucklebusted, Jan 29, 2022.

  1. knucklebusted

    knucklebusted Well-Known Member

    By may math, the DCR drops .25 with the 290 cam at 7.29DCR compared to the 212 cam 7.48DCR in the same configuration, straight up. Installing it 4° advanced (as most stock timing sets are built) raises it to 7.65DCR.

    Here's my spreadsheet if anyone wants to play with it.

    Auto Math Spreadsheet - Go to the Engine Info tab to see it.
    patwhac and Dano like this.
  2. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    these gutless 4 bangers with a ton of gears dont really help around here. in my wifes equinox it was always staying in a lower gear. it got worse gas mpg than a v6 or v8. it also felt gutless and hunted for gears. they may do good in flat city land with no curves. mountains it was pretty terrible.
    knucklebusted and PGSS like this.
  3. knucklebusted

    knucklebusted Well-Known Member

    They hadn't started on the block yet so I upped the milling on the deck to .020 to improve my chances of getting to about 9:1 SCR.

    With a TA 212, that will yield the following: Shave heads .010, deck block .020, steel shim head gaskets, .030 pistons in bore and straight up cam install.

    Static compression ratio is 9:1, Dynamic compression ratio is 7.76:1
  4. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    i dont want to take my block apart so im better to have my heads alone to .30 or so right
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  5. knucklebusted

    knucklebusted Well-Known Member

    Taking .030 off the heads isn't as good as taking .030 off the block but it will definitely help. If you know the CC difference, we can plug it into the calculator to see where it winds up.
  6. nekkidhillbilly

    nekkidhillbilly escaped mental patient

    have no clue. im wanting to be right where you are on cr. i planned to get the heads to the machine shop back last summer and my wife lost her job due to covid and we have had seat back after seat back ever since and its winter on top of it now. she does have a good job now.
    knucklebusted likes this.

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