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Dear Valued Home Depot Customer, We have reached out to the manufacturer and their answer is,approximately 1,900 psi
Would that be horizontal or vertical ?
It can't be an even 3 feet as blocks are 8" high So what you can have is a wall 4 blocks high at 32" - 576 blocks or 5 blocks high at 40" using 720 blocks
https://www.wikihow.com/Cut-Cinder-Block This site will give you all the information with pic's