I have a 64 409 truck block that cleaned up at 4.390. I am planning to use (but have not yet bought) the ICON IC979.078 pistons. This is a 340 HP engine - correct 817 heads. I need the cc volume of the truck notch to do some pre-mockup calcs on the compression ratio plan. Goal is 9.75:1. I recall from years ago that the truck notch volume was of the order of 10-12-15 cc as a rough number. Hoping some "truck block" veterans can fill in the missing notch cc number. If someone has been down this research path with the ICON .078 pistons please jump in!