[FE427TP]

no, half of that. Half of the stroke is gained on the bottom of the stroke, and half of it on the top. So the piston would only be .140 deeper. If the 390 was .280 higher than the 360 on the top of the stroke it would be .280 deeper on the bottom of the stroke too for a .560" longer stroke, but it's only .140 higher on top and .140 lower on bottom for .280, but it's really late for me right now so if none of that made sense sorry. and the 360's had 8:1 compression or less, it seems like they even went down to 7.4:1 at one point...