swap will be the best for the value.... might as well. your block is obviously gone to sh*t... probably part of the head too. sooooo, just get another B-series....with your 1990....take your pic
B16 first gen, B18A, B18B (better than the B18A), B17A, B18C1, B18C5, B20B, B20Z (better than the B20B). oh, but dont forget to get a new tranny if you get a vtec b-series.

i say just get a B20B/Z and squeeze a tiny bit of nitrous and youll be flying.