newbie with a gsl-se

[FBob13]

i have an 85 gsl-se thats in great condition. i got it off of a guy who said he just replaced the engine, i did an atf treatment to be sure and replaced the spark plugs, wires and rotor cap. the car would continue to turn over and spudder but i couldnt get it to start up on its own. i checked for fuel delivery and spark and they came out good. it seems to me that the engine is flooding out. i dont have a compression tester though so i'm kinda of scared but i see no blue smoke out of the exhaust when its turning over. is there another series of diagnostics test help diagnose. i'm hoping its my injector seal rings and that would be a comparetively cheaper fix. but any input is greatly appreciated.