Does anyone have any information? is there any big difference between the 5.4 SOHC in a 1998 Expy and the DOHC 5.4 in a Navigator? would an M5OD bolt up to it and not expolded after 10 miles? Thanks for your input!

 

The heads are much larger, the power band is higher and they have about 40 more HP. I would doubt that the M5OD would hold up long behind a 5.4L SOHC much less a DOHC. That's why Ford never put that tranny behind any 5.4L.

 

I was just wondering this. I just bought an 02 f150 with a 5.4. My grandpa has a navigator i think its 01 with a 5.4 and that thing screams, i really wish my 5.4 ran like that one. are the head the only difference between the two

 

Heads, intake, exhaust, wiring, computer, more compression 9.5 vs 9, possibly the pistons are different too.

 

Ive heard the best route would be a super duty five speed as the six is physially to large to fit without some body modification. im not really looking for engine parts interchangability, im curious as to wheather or not an M5OD, or an M5R2 as the case may be, would bolt to the same year Navigator enigne block. The idea would be the entire hybrid "Navigator/F250Engine/Transmission/Computer/T-case" combo would be put in my 1998 expedition

 

It should bolt up the either engine. I would definalely use the ZF 5-speed over the M5OD. I'm not sure of the actual dimensions as far as fitting in your truck or not.

 

I ouldn't bet on the ZF5 being an easy fit in an F150, either, unless there's a recent run of ZF5-equipped F150's I've been missing out on that came from the factory so equipped.

Just keep a slushbox with the DOHCer...you can build that up a lot easier than a Mazda tranny and you can chip the computer and get better shifts from the tranny anyway.

 

I've never compared the two trannies, so I wasn't sure. I would use a 4R100 auto tranny if I have the option.

 

Going from non-PI heads to PI heads (basically bolting them on) will yield a high compression ration of around 10.5:1 or so...I thought about doing this but the CR was just too high for a blower IMHO so I didn't do it.

I'd imagine jumping to 32V heads would be similar but I'm not 100% certain about the shape of the 32V combusiton chamber.