Help?

so. dont think this is correct- i tried converting a wood block from scrap mechanic into a real world weight so i could prove it might be a good resource to my science teacher. but according to my calculations- a single wood block is about uh- 158.66lbs give or take. im fairly sure i got my math wrong would anybody mind helping me? i only need the wood block done as according to scrap mechanic it is 1 unit, and then i can just find the weights of the other blocks through the unit system- (whether they make sense or not.) so uh, yeah? k cool- cya around-