im looking to trade my cousin for his sr20 swapped s13 hatch. he freshly rebuilt the motor and the first time that he started it it ran for about 45 minutes then the head gasket blew. well he had the head checked and it was fine and im assuming that the block was checked when he rebuilt the motor, but after he changed the head gasket he said it started for a short time and ran then died and wouldnt start again so i have a few questions that i couldnt find the answer to poking around on this forum. first thing, is this motor interference or non interference? as im sure some of you are figuring like me his timing could have been wrong. just worried that maybe he dropped a valve. after that im not sure what else i would look for outside of the common things like fuel, spark and checking sensors to be sure that everything got plugged back in sufficiently. thanks in advance

Start out checking your basic things like you said (spark, fuel, disconnected grounds, unplug sensors, etc). If the head was ripped off it might not hurt to do a compression test to make sure the timing was done properly. If you get 0 compression then your timing is mostly off.