85 crx engine

I need to know if i can put a motor from a year other than an 85 in my 85 crx. Also i need to know if i can put a v-tech in it without having to do much modification.

any 84-87 civic/crx mortor will fit. also the 86-89 integra motor, the 86-87 version of that motor is almost a direct swap into the CRX Si. puting a vtec motor requires quite a bit of time and money, hasport makes a mounting kit but you'll need custom axles, a vtec wiring harnes, ecu and a bunch of other stuff.