3barboost

hiya

ok I am planning an engine swap in my 2002 NB chassis

I have found a complete 4.6 V8 Mustang engine and manual box

I have fitted a Lexus V8 into a NA chassis (removed all chassis rails and solid mounted it) the lexus v8 had a supercharger and made close to 440hp to the tyres

by tape measure I can see I will have to do the same thing - about 65cm across the oem exhaust manifolds - trim the rails and theres enough space, and with headers that aim down rather than out a bit I can gain a few cm there

what I want to know is the 4.6V8 worth the effort ?
300 odd HP ?

an equivalent LSx motor and manual box is about 35% more expensive where I am

I was previously limited by tyre in my NA

I do want decent power but as i am a few years older it doesnt need to be stupid power !

will the 3valve 4.6 V8 do the job or do i cough for the LSx ? or what other options ?

I am even thinking v12 BMW or Mercedes !

Gator Bait

4.8L LSx can be had for a few hundred bucks all day long in most places I've seen. Bolt in kits and no guess work fitment. ...but in for watching the build for certain!

3barboost

Ok but I am located in South Africa
As an example a used ls2 from a grand Cherokee is a 5k usd motor !!!! No box

I can get the completed mustang v8 engine and box at under 4k usd complete

A Toyota v8 and manual box change is 3.5k usd

Gator Bait

Devil is in the details!

MRM331

Grand Cherokees have LSx engines in them in South Africa?

If you are planning to try to fit the 4.6 have you thought about going with the newer Coyote 5.0? It's more powerful and slightly smaller in most dimensions. 4.6's have been done although I've never actually seen one running. The exhaust, as you noted, is the biggest issue.

-Jason

3barboost

hi yeah we have the LS with cylinder deactivation here in SA
in the JEEP Grand Cherokee

there are no 5.0 available - its not an official import
neither is the 4.6

the 4.6 appeals as it comes with the box / flywheel / gear linkage etc

the Chev motor would be an auto motor and then i need to source a box / flywheel etc etc

I am trying to weigh up all options in my head

the LS is the way to go but geographically / cost its a challenge

my previous V8 Miata was a hoot to drive with a supercharged 4 litre toyota motor (probably as wide as the 4.6) and I got that into the NA

or do I look to a BMW / Mercedes V8 ? -they are more common and cheaper here in RSA ? and look no harder to fit than the 4.6 / Lexus V8

V8droptop

I'd be looking for a 90 degree ohv V8, they just fit so much better in the
chassis with less work. The less cutting you do the more you retain the original cars integrity. Believe me, I see failed weld's and broken fab work daily, including 5 or so examples this morning. In this case, less is more, in modification vs reliability. I'm sure it could be done well, but a sbc/sbf/ls is a better fit. I would even consider an audI v8 with chain or similar, but probably not cost effecive, the dohc again add complexity and size to small packaged car.

Just my opinion, I think you have the right idea in letting the measuring tape do the decision making. Can you get ahold of a used aussie ute by chance? The truck /van ls motors would be nice but i suppose they don't have 4.8 5.3 and 6.0s there?

I do think the 4.6 would be interesting, with ohc layout maybe revving and delivering power in a fun way in the miata. I really want an excuse to use an rs4 v8 (8000rpm redline) in a car some day, but i think reliability is a good thing to consider in this case.

3barboost

We have some of the aussie UTEs here with the 5.7 litre of 6.0 litre LS motor almost all with an auto and you looking for at least 5k usd for the LS motor alone, there are one or two LT1 around without a box for about 2k usd
my worry on the 4.6 is if i break it - where will i find a replacement ?
this is what made me do the toyota v8 previously i would love a 6litre in the miata ! !
the audi v8 appeals but quite a lot of work on the sump is required - they have a chain driven oil pump living where the steering rack lives (same with most bmw and mercedes motors)

the 4.6 is already rear sump and manual....... talk me out of it !!!!

mazdaspeedmiata

if there are more lexus 1uz around in your area i think you'll have better luck getting one of those fit in a miata

there are even pictures here
Starting a 1UZFE conversion - MX-5 Miata Forum

charchri4

+1 to the lexus and the car he ^ mentioned is for sale now here with lots of good photos. https://www.v8miata.net/cars-sale-4/...-hardtop-2074/

You could probably pick his brain on how he did it. There is a pretty good video of it here too https://www.youtube.com/watch?v=8EsO...ature=youtu.be

Welcome to the forum what ever you do I can't wait to see it!

.boB

Is it worth it? Yeah, I think it is. The 4.6 is an excellent motor. Makes good power, very efficient, runs easily to 7,000 rpms, and makes torque all day long. For it's size and cost (for you) it would be tough to beat.

In the US the mod motor is not a popular swap choice, simply because of it's external dimensions. For only having 4.6L displacement, it's quite large externally. But you find it in a lot of kit cars and classic cars anyway. I dream of a Daytona Coupe with mod motor.

3barboost

Hi

I have already done a lexus V8 (with a supercharger / 8.8 rear end / f355 brakes etc) and to be honest it wasnt that difficult - it ran a 10.8 on the 1/4mile

so it was silly fast but it was stripped and rough as a bears a$$
nothing under the dash / paint rough etc it was fun and turned tyres to smoke regularly

I actually measured the Lexus across the oem manifolds and it comes out to 65CM

the 4.6V8 cames out at 64.5cm so small difference so I know I can fit it
I just want "confirmation" its worthwhile

I would like bigger displacement (without boost as a replacement) to be honest but not sure if its worth the extra cost

3barboost

here's a few pics of my Lexus V8 - supercharged Miata ! - since sold - hence the scratch for another one

mazdaspeedmiata

oh so u know what you are doing already ....

heres another one for u
Matt's 1990 1UZ Project - MX-5 Miata Forum

3barboost

Thanks for the link
Hardly know what I am doing

I just know I can do better second time around !

I like bobs view on the 4.6 !

Seems a possible oil pump replacement is all that's needed on that motor to keep it stock reliable

What will be a nice touch I think is fomoco actually retailed the miata here so I have fomoco tag in the engine bay so I can just tell the uninitiated that its the stock engine......

3barboost

So as an update I pulled the trigger on Mustang GT motor !
and have a buyer for the old Mazda drivetrain !

time for a build thread !

577nitro

Best of luck there, and yes plan on a build link. I would like to do a Ford, ,and thought about the Coyote, but have zero knowledge with the motor, so will be looking on with great interest. Most of my efforts in the past have been with SBCs. If I do go the Ford path , I will put the weber downdrafts on it.