I currently have turbo ls/vtec but I am trying to build another turbo ls/vtec but I want this block to be sleeved. I can get a a1 block for very cheap but what is the difference between b1 and a1 if I am getting it sleeved? Sensors, oil ports, bolts, anything???

 

on a 96 and newer b18b the pcv system is deleted off the block so if you put in an older motor (unless you had a a 95 ls block) you will have to add a catch can and a freeze plug to the hole...I dont think the older motors had a knock sensor either,if Im not mistaken which I could be, but thats not a big deal either just drill and tap a hole. The biggest differences in between the As and Bs was the intake manifold which you are not using anyways