advice for swapping from a 2.5L to a 4.2L

Look, I am buying a 89 wrangler with a 4.2L with 5spd tranny for realy cheap and i currently drive a 88 wrangler with a 2.5L with 5spd tranny i want to swap the enginesand complete driveline and i want to get the 4.0L feul injection system alone with the intake manifold and i was wondering if anyone had any incitte as to if i have to take the 4.0L head or if the intake manifold will bolt right up to the 4.2L head. i know i will have to buy the wiring harness and computer for the 4.0L and i was jus wondering if anyone has done this or would know where i could get more information and if i could have any advice and such for a project as large as this

thanx
sarge