i know this post is like 2 years old, but i came across it, which means someone else could too. so i'm gonna post advice. get rid of the hf!

the 88-91 hf's came with d15b6 engines. 8 valve non v-tec. you can't swap any head on it. plus the block can't handle rev-ing past 5500rpms. for $1400, he might as well go with a b16. as long as it's the jdm b16a1 from the jdm crx si-r. then he could basically drop it in, with the help of the si vacuum line system. he just needs the motor mounts from hasport (or someone else) which should only cost about 300-400 max. i assume the b16 is the package deal of course. engine, tranny, intake/exhaust manifolds, ecu, harness, etc.....

i wouldn't mess with anything else. the entire vacuum line setup is different from the other crx's and from any of the civics. unless he really wants to swap in the vacuum lines and the engine from the si, it's not worth it.

do yourself a favor and get rid of the hf. get an si and it'll be much easier. go for the 90-91 si too. they have rear disc brakes stock!