I have no clue if it's possible, but what about changing the tranny to the CRX HF tranny. Gear ratio is great!
88-91 CRX HF
Final Drive 2.954 (3.250 in California)
Just a suggestion, stay away from anything in CA. They have different emissions laws, and often things (trannys, etc), get built a bit differently. Resulting in worse mileage.