10.5:1 273 pistons with 360 heads compression ??

Motor as it sits
3.63 bore
Deck height unknown
2bbl Piston -.003 down
Gasket size 4.06 x .039
920 273 heads 62cc chamber (guess)

Option one
3.63 bore
Deck height unknown
2bbl pistons -.003 down
Gasket size 3.70 x .028
308 360 heads 70cc chamber (guess)
(Maybe cut head -.020. -.030)

Option two
3.63 bore
Deck height unknown
4bbl pistons +.139 height difference
Gasket size 3.70 x .028
308 360 heads 70cc chamber (guess)