won't save much gas if that iddy biddy engine is pulling that heavier body.
i agree with the opinion that you should find a whole HF and fix it up.
i had an old 1st gen crx hf model back in the day, and, honestly, in its ripe old age, it got the same gas milage that my 2nd gen crx DX is getting. roughly 35 - 38 mpg.
i'd probably do better if i knew more about engines and had the tools, time, and extra vehicle lying around to be able to rebuild everything.