Super-Dome Compression Ratio

Roger Harmon

Guys,

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

R/ Roger.

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[Deleted User]

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.

53jetman

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.

Roger Harmon

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.

[Deleted User]

RODGER I HAVE A CAST IRON SUPER POWER DOME HEAD ON MY 52 HUDSON. PART NUMBER 305854 7.2

dougson

Roger Harmon wrote:

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).