I have a 94 crown vic wanting some more power it's a p74 I have the opportunity to buy a police interceptor engine. My question Is what years of the crown vic PI engines will fit my 94 crown lx?

The civilian and PI Crown Vics are both 4.6 Modulars. You will gain little to nothing, 190HP P74 and the PI has dual exhaust and gearing, some other mods like an oil cooler. If your present engine is in good shape you will waste a lot of money for nothing.

http://www.crownvic.net/news/lomag.shtml

Ok that's what I heard. What could I do to gain some noticeable power it needs something could I drop like a 302 or 351 in there? Pretty easily

The 4.6L DOHC engine from the Mustang Cobra and Lincoln, will fit in the Crown Victoria. 300HP. The 4.6 P74 is a SOHC. The Dual Overhead Cams are the trick.

Do you have to change the harness?

I was done after I posted that yesterday, sorry I didn't get back to you. Yes, you will have to have everything from donor car. Or if you buy a crate engine, yes, you will need an ECU, your present one won't work. But if you have the money, you can drop in a 5.0 - 32 valve Coyote 400HP. If I ever built a hot-rod, I would use The Panther Platform (what you have) and this engine. One of the sweetest engines there is. $5500

There is even another if you are rich. All fantasy to me. But there is the 500+Hp Ford Mustang GT 11-14 302 (5.0) One of the very few engines ever produced (street legal) the exceeds the HP to CC ratio. Other words few engines put out 1HP for 1 CC. $16,500

What if I take a motor from a 96 Mustang GT and put in my 95 Grand Marquis? Will it fit in ok? Computer?