3.8 to a 5.0? or a 4.6 dohc?
 

I'm not sure if the original 5.0 were dohc or not, but i do know the newer 4.6 are. What type of conversion would i need for both options here, and how much would each cost?

I dont know the specifics but I can tell you that a 5.0 conversion would be way easier and way cheaper.

I own a 4.6 DOHC cobra and a 5.0. And let me tell ya a 4.6 DOHC engine is wider than a big block engine.

IMO my 5.0 is funner to drive than my cobra cause it has way more torque.

If it were me I would drop a 351 in there.

BTW: The 5.0 HO is a push rod engine.

You think a 351 could really fit in there? I thought about that as well, but just ruled it out since i thought it was too big to fit. What stock HP is a 351? I found a 302 with 350 stock.

The 4v 4.6 is DOHC
The 2v 4.6 is SOHC
and The 5.0 is push rod like dark said.

351W would fit. HP depends on what you get it from (truck, crown vic, or create). The 4.6 is a wider engine so if it fits than the 351/302 will fit. MAy need a new hood depending. I would also have to say that the 302/351 would be an easier swap. Depending it may be cheaper to just go buy a different car unless you want the fun of swapping an engine.