Will a olds 403 fit a 2000 pontiac sunfire gt?

Why would you want to even bother fitting a 403cid engine into a space that used to take a 104cid engine? Apart from the obvious fact that everyone else has said in needing to convert a previously East-West FWD engined car to even make it capable to take a North-South RWD car, there is the even more obvious problem of making an engine not quite four times as big fit into the bloody hole. How? If you were even to attempt such a thing, you'd probably have to dismantle everything forward of the firewall, and then strengthen the body itself so that you didn't torque flex every single weld in the car to pieces. This is such a hideously complicated engineering job, that it's simply not worth the effort.

The 403 V-8 is for a rear wheel drive car, & the sunfire is a front wheel drive. Sorry, couldn't do that without a 5# box of $$$.

If you have the time, money and know how to completely re-engineer the car, then yes you can. But asking such a question in the the first place suggests that you don't. You would end up spending tens of thousands of dollars making this work, and when you were done it wouldn't be street legal. Funnily enough, for all that work you would have a total gain of 35 HP to show for it. As the stock 2.4L in the Sunfire was good for 150 HP and the 403 coughs out a whopping 185 HP. All and all an asinine idea.