hi how could i tell if my b16a motor is jdm or usd and how could i estimate how much milage is on it

 

ask it ?

 

Higher compression ratio. As for miles it's just an educated guess. You could do a compression test and see how good the rings are and head gasket. If good numbers come out then either it has new rings or the motor is nice and healthy. Then you could also look at the timing belt too se if there's any fraying, nicks, worn down belt teeth, or dry rot.