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Super-Dome Compression Ratio
  • Roger HarmonRoger Harmon
    Posts: 201Gold Member
    Guys,

    What would the compression ratio for this head be, before surfacing?

    R/ Roger.

    http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=300511397736&viewitem=&sspagename=STRK:MEWAX:IT
    R/ Roger.
  • walts garage-53
    Posts: 1,486Platinum Member
    Rogers, I can supply you with a pair of TWIN-H-CARBS for a 308 engine. All HUDSON always said was 100 pounds compression. All cylinder heads are 2 inches thick and 0.060 was all they recommended to surface. Valves will hit the head. Did you receive my shipment? Walt.
  • 53jetman53jetman
    Posts: 880Platinum Member
    CR of cast iron head was 6.7, and the aluminum Super Power Dome was 7.2. Remembering the problems we used to have with blown head gaskets on Hornet engines with aluminum heads, I would certainly not recommend it's use. Better to have the cast iron head milled to near max which would probably equal the compression of the aluminum head.
    Jerry
    email: HudsonJetman@mail.com
    2nd Generation Hud-Nut
    HET Tech Adviser on Hudson Jets 1953 & 1954
    HET Registrar of all Hudson Jets
  • Roger HarmonRoger Harmon
    Posts: 201Gold Member
    All,
    Thanks for the help. I figured it was around 7:1.
    Can you tell from the part number if it's for a narrow or wide 262, or is that only for 232's?

    Walt; I sent you a PM.

    R/ Roger.
    R/ Roger.
  • hudnut52hudnut52
    Posts: 111Senior Contributor
    RODGER I HAVE A CAST IRON SUPER POWER DOME HEAD ON MY 52 HUDSON. PART NUMBER 305854 7.2
  • dougsondougson
    Posts: 601Platinum Member
    All,
    Thanks for the help. I figured it was around 7:1.
    Can you tell from the part number if it's for a narrow or wide 262, or is that only for 232's?

    Based on the number on the head it is a wide block 262 that was optional on Wasps, Commodores, and Super Wasps from 1951 to 1954. The compression ratio was 7.2:1 from 51 to 53, 7.5 in '54. Why the different CRs did not get individual numbers is beyond me. So if you know the year of the vehicle it came off, you should know the compression ratio. If you intend to put it on a 308 the compression ratio will increase because of the increased bore, but if the block is relieved, maybe lower. To figure the compression you will need the area of the cylinder, piston/deck gap, and combustion chamber (including valve relief if there is one).