and you already have an engine installed that doesn't require custom work and will still result in drivability issues.
replace the current headgaskets in the car = easier than an engine swap.
it'll bolt right up but you need to swap the entire intake manifold wiring harness - move it from one intake to the other. then it won't idle correctly because the idle controller set ups are completely different and non interchangeable (well not without significant custom fabrication). after cobbling it together you can prop the throttle plate open to get it to move.
or you could do a complete wiring/ECU merge...but you're likely not going to do that and it would be far more work than doing the headgaskets.