caculating compression ratio

I have a friend's son that is building his first motor. 350 SBC. He's running flat top pistons (double eyebrow reliefs) Stock 4 in bore
Stock 3.48 stroke
He just bought some heads and the machine shop brought the chambers down to 66cc. Which had me a little worried at first. Seemed small to me off the top of my head. Assuming the piston deck height is near zero. (stock rods and crank) and with a head gasket of around .039 (thick FelPro)
I'm coming up with around 10.25 or so with this caculator.
I entered zero on the dome piston volume. ( know it should be very slight neg with the eyebrows) Used the default positive piston deck height entry. .016 Head Gasket thickness .039 And the default head gasket bore 4.03 Stroke 3.48 Bore 4.0
Sound reasonable? 10.25 would be just about right for him. Anything over 10.5 and I would be worried for him... The heads are iron heads, so I'm figuring 10.25 to a max of 10.5 for him and the kid doesn't need to detonate it all the time and burn pistons..
Ric Seyler
Online Racing: RicSeyler
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