So I am debating which DOHC v8 to use...

wicked93gs

15 Year Member
Sep 30, 2006
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Nashville TN
well, I ordered my MII kit, so I could put in a DOHC v8 engine...I was fixated on the Cobra/MarkVII/Marauder engine for a long time, but recently other ford(or ford related DOHC V8s have come to my attention....first up we have an 03-05 Lincoln LS V8...very tempting engine...its 3.9L DOHC 4 valve engine rated at 290ish HP with equivalent torque...the lincoln LS came RWD with a 5 speed option so the tranny would be easy enough to figure out, also I can find them used for $500-$800 with decent mileage

Next up we have a 4.2L version of the same engine...this time used in the Jag xk8 rated at 310HP/300TQ, if I look hard I can find a decent mileage example for $1000-$1200(also available in supercharged versions up to 500HP for about $3000)

Next we have an 05 Volvo XC90 engine...DOHC 4.4L V8, produced by yamaha for ford(similar to the SHO engines..I am dismissing the SHO v8 from this list simply because its discontinued and doesnt make enough power...also hard to find one that the cam gears aret already messed up on) anyway this engine makes 320HP/340TQ....but has the issue of being a FWD/AWD setup...meaning to make it RWD I would need to do some adapter plate/bellhousing work and still have to figure something out for a pilot bearing....a lot of work....another issue with this engine is its expensive...$3500 if you can find one

Another engine I have been considering is the new 3.7L DOHC V6 Duratec engine...rated at 275HP/270TQ....the main issue being very hard to find since this engine is so new(09+ models)

And then of course the tried and true 4.6L DOHC V8 from the Cobra/MarkVIII/Marauder varying from 280-300HP(roughly the same torque) the mark VIII versions are fairly cheap and can be found for roughly the same cost as the LS v8 engines

what do you guys think? right now I am depating between the Mark VIII engine and the LS V8 engine...virtually identical in power output and cost...I can however find LS v8 engines with lower mileage easier and I am thinking the smaller displacement of the LS v8 engine would make it somewhat lighter...though I would have to either get a tranny to fit it, or adapt the t5 I have....which might end up costing more, but would probably come out with better gear ratios
 
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I'm glad you are sticking to the DOHC/4v motors. A SOCH/2v motor isn't even worth the time of day unless you buy a set of aftermarket heads which jumps the price quite a bit.

The 03-04 Cobra motor has the best internals but the weakest block, if you aren't going to build for high HP/TQ then it doesn't matter as it will take between 500-600hp without much issue. The 03-04 motors are also supercharged, they make quite a bit of power and are easy to make go faster with a minor mod such as a pully for the blower.

The 03-04 Mach 1 motor has a stronger block then the Cobra block and the same forged crank (if you get a stick shift motor, autos had a cast crank), they have the same heads as the Corba and you can usually get these motors cheaper. I've heard you can get a Terminator Cobra supercharged take off for under 1000 bux if you want more power out of the motor for cheap. The Mach 1 motor made over 300 at the wheels bone stock. This motor is my favorite 4.6L v4 (and I drive a Mach 1 every day... no bias there).

What I would do if I were you is, go with the 5.4 motor. There is no replacement for displacement and it is a lot more original then a 4.6L as not too many people do it. The main hurdle with this motor was finding a good intake manifold. The 2000 Cobra R intake is unavailable. Recently, someone found that there is an Australian intake manifold for the 5.4L which is almost as good as the R intake and now the 5.4L motors can breath and make some real power. This was the key to figuring out how to make the 5.4L swap viable. You can pull a motor out of a Lighning if you can find one. There are other cars/trucks that came with this motor as well, but not too many came with the blower. I think the Harley F150 came with a blower as well.

All that being said, I would go pushrod in a classic, but thats just me. I don't like the 4.6L motor in my Mach as much as I like the 5.0 in my 67. I also definately don't like the 5.4L as much as the 351w which I have nothing to put it in to.....
 
I know about the XR8 australian engines, or the FPV, whatever they are called(from the falcons and utes)....personally it would seem simpler just to make a sheet metal intake....the only issue would be determining what runner length I would need...I like the idea of a 5.4L....I don't care about the supercharger, I would rather not have one, I just don't think they hold a candle to turbos if I decide to boost the thing...as for classic engines in classics, honestly I could care less, I just like 4 valve engines, unless its a shelby or some other very limited mustang...mine is just a coupe though so its no big loss.

I have seriously been considering both the 3.7L duratech and the 3.9L LS engine though just for something different(if I dont get a 5.4L)
 
the only thing I dont like about the 5.4L is that it is 120lbs heavier than the aluminum block 4.6L, I am trying not to go over the weight of the stock 289...trying to make this car as lightweight as possible(one of the reasons I want the 3.7L duratec....that thing weighs in at 300lbs and I wouldnt take much of a HP/TQ hit over the 4.6L, also being shorter it might make for a slightly better handling car...I'll need all the help in that department I can get with the mustang II front suspension....so sadly because of the weight, I am disqualifying the 5.4L, much as I would love that engine, I'll just have to boost a smaller engine instead
 
I'll look into the weight of the 5.4L and get back to you. I have a hard time believing that the aluminum 5.4L is that heavy when compaired to an all cast iron 289. Now a 289 with aluminum heads and intake, thats another story.
 
how about an LS1?

if you want to stay ford, my vote is definitely the 4.6L 4V cobra motor. The earlier (99-01) blocks were alum which helps the weight quite a bit. plus you can go t45, t4650 or t56 which will all make great power and reliability. Plus they will be easy to swap since many ppl have doen this before. and your turbo dreams can come true with this as well!
 
no LS1, not that the engine has to be ford(I just prefer Ford...a caddy northstar engine is tempting though), but if I was going pushrod 2-valve I wouldnt have ordered the MII suspension, the info I found with a google search says the 5.4L is 560ish lbs or so, a pretty big gain over a 289/302, otherwise that would be the engine for me, after looking into the 3.5L/3.7L duratec it looks like RWD conversion on that engine would be problematic...not impossibly so though, still a possibility, but the 4.6 so far is the path of least resistance
 
how about an LS1?

if you want to stay ford, my vote is definitely the 4.6L 4V cobra motor. The earlier (99-01) blocks were alum which helps the weight quite a bit. plus you can go t45, t4650 or t56 which will all make great power and reliability. Plus they will be easy to swap since many ppl have doen this before. and your turbo dreams can come true with this as well!

Only the Terminator Cobra had the cast iron 4.6L (at least for Mustangs). The Mach 1 motor is aluminum and has the better Terminator Cobra head. The advantage of the Terminator block is that it comes with forged crank/pistons/rods. Stick Mach 1 motors came with the same forged crank but not the rods or pistons.
 
I take it that 4-cylinder engines are ruled out? If so, I think the Lincoln V8 sounds like it fits your criteria the best. I may even consider it as a swap candidate for myself in the future.

The purists will hate me for suggesting this, but have you looked into the midsized Toyota/Nissan V8s? I don't know what they weigh, but I do know that many are all-aluminum and quite overbuilt. The Nissan/Infiniti VH45 comes to mind.
 
yeah, no 4 cylinders, I'm going to make as much use of the extra space as I can...with an engine weight limit of 460lbs....while the nissan engines are nice, I dont hink i would put one in classic american car(though the DOHC 4.6L is really a Fiat engine, at least it carries the Ford name) I have almost decided on the 4.6L....mainly because the 01 v6 T5 tranny I have I have found has 3 bolt holes that will line up with the block...and after drilling out 2 mounting bosses, I can have a total of 5 bolts holding the engine and tranny together....input shaft length is correct, the cobra and the v6 use the same size and splined clutch, the starter will line up with the flywheel and with just a few mods I'll be able to use this tranny, so a this point the 3.9L is no longer as tempting(though it would still be cool to use just for something different)
 
how about an LS1?

if you want to stay ford, my vote is definitely the 4.6L 4V cobra motor. The earlier (99-01) blocks were alum which helps the weight quite a bit. plus you can go t45, t4650 or t56 which will all make great power and reliability. Plus they will be easy to swap since many ppl have doen this before. and your turbo dreams can come true with this as well!

I agree. I would go with a DOHC 4.6 Cobra motor or the Maurader etc with comparable motor.
 
I'd love an ecoboost engine...but I'm not waiting anymore....I've had the car 2 years now and the only thing I have done up until I ordered the mII kit was a 8.8" rear with rear discs and some minor sheet metal work...its time to get cracking on the project, I want it drieveable by the end of the summer
 
Another engine I have been considering is the new 3.7L DOHC V6 Duratec engine...rated at 275HP/270TQ....the main issue being very hard to find since this engine is so new(09+ models)

And then of course the tried and true 4.6L DOHC V8 from the Cobra/MarkVIII/Marauder varying from 280-300HP(roughly the same torque) the mark VIII versions are fairly cheap and can be found for roughly the same cost as the LS v8 engines

If you like the new 3.7L, just wait til '10 when the 3.5L turbo version comes out in the new Lincoln. Supposedly will be rated at ~400hp. Ford was/is experimenting with putting these in the Expedition/Navigator to give you an idea what kind of power they are capable of.

Im no Mod motor expert, but blocks on the 05+ 3v Mustang engines will handle 1,000hp or more. I have a hard time believing the terminator motors are weaker than that, especially given how fast some people are running with them.

Or, you could just stab in a painfully bland 302 to get the car going and work out any bugs while you find exactly what you want for a final engine.
 
the ecoboost engine is the planned 3.7L turbo....the duratec engines are capable of big power(as you can see by the Noble M12) I'm getting a 4.6L DOHC in a couple days...barring any amazing deals on alternatives