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280z Ford 4.6L Mod Motor


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Hi all

I’m usually not one for build threads for my projects.

But I thought I might throw something to together here. There seems so be a few abandoned 4.6L mod motor threads.


First off I have to give major props to yellowoctupus pretty much pioneered the way for the mod motor swap to make us believe it was possible with an excellent write up and knowledge.


It's a budget build, parts and these engines are everywhere.


I have a 78 280z. I purchased a 1999 Mustang GT donor car, drove the mustang for a month made sure everything was good to go on it. Engine has 100,000km on it, yes kilometers with a newer crate T45 transmission with 5000km.

Bought a SCT Tuner, programmed the tune to Delete: Rear O2 sensors, EGR, Return less fuel system, PATS anti-theft, and 91 octane tune. Tune shop suspects just over 300hp with this tune they have used so many times.









Edited by bimmota
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I cut the engine cradle out of the mustang to modify to fit into the Z. Trimmed it to fit between the frame rails

I welded 2.5”x2.5” angle iron to the frame rails for added support and twisting.

The engine cleaned up quite well. 

Dropped in the engine in for a test fit to see how it fit. Just enough room.








Edited by bimmota
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I also had fitment issues with my oil pressure sender / coolant neck. So I cut it and tapped pipe threads with fittings for the oil pressure sender. Which doesn't do anything at the moment need it swap it out for a Z sending unit for my gauges to function.


IMG_3136.thumb.JPG.0b00eec3ace9117773107cf8f1c5a5de.JPGto work.



The stock mustang rubber mounts have to much movement for my liking so I upgraded all of them.IMG_3075.thumb.JPG.30f95353d7ddba3e935cee81193a2244.JPG


At this time I built the trans mount as well



I went with the high volume Wilwood M/C 3/4" and Wilwood pull type slave for the clutch set up we will see how they hold up.IMG_3134.thumb.JPG.7b2e2782d0f05b5de18d682fabdfac32.JPG




After buying 7 belts finally found the winner to delete the P/S and the A/C.


And the oil filter doesn't fit so I found a shorter filter to be able to unscrew it when it comes to time for an oil change.



Now time for a new fuel rail to get rid of the return less fuel system. I was going to go after market but after lots of research and complaints after market rails don't like to fit with MSD coil on plugs. I wasn't about to spend $700 on rails to to make the engine's fuel return to the tank.

Went to the junk yard lucked out found the exact same style of fuel rail from a 99 crown vic that was a return style fit like a gem.


Made a EGR block off plate



After having the engine in and out so many times, wore out the threads on my engine leveler. finally got in the spot I wanted as far back as possible and and high as possible.

There's about a 1/4 ish gap between the throttle body and the hood. 













Edited by bimmota
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Once the engine was sitting all mounted up. Started on the down pipes. Used the factory exhaust manifolds with flanges. Had to use the 2 1/4" for a few inchs for clearance then expanded to 2.5" dual exhaust. Couldn't seem to track down a spare diff mount to modify for true dual s, so I just Y pipped it dual 2.5" to 3" out to a Borla XR-1 muffler.











Edited by bimmota
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These T45 transmission are glass pretty sure I bent a shift fork into 4th gear when it was still in the mustang day 3 of driving it. So I got a MGW short throw with the back stops to prevent you from over shifting and taking out the transmission.

The location isn't quite in the factory Z spot little more forward need to extend the  shifter  to be comfortable and so I don't hit my knuckles on the dash.



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Very nice. How much of a headache was reusing the stock engine harnes? Just a few wires? The engine doesn’t look like it sits too low at all, how does it compare to stock?  Are the 4.6 taller than the LS everyone else seems to me using?

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Once I found the correct diagrams I was able to make sense of it. So many different variations of wiring diagrams for the ECU. I tried to use as little of the mustang harness as I could. I did keep the CCRM - constant control relay module which has 5 relays built into it I'm only using the PCM relay in the unit. I believe there were 5 grounds coming off the ecu and 2 vehicle powers I fused to switch power to the CCRM. Fuel pump was wired as a standalone circuit. Didn't use any of the mustang fuses.

I was battling the wiring for while, the car would want to fire seemed like it was running on 2 cyl. Stepped back started over put 6-7 ground straps all over the engine to chassis flashed up in half a turn of the starter. I know grounds are important I had a few added a few more made the difference. 


The engine sits about 1 1/4" below the stock z front sub frame.


I'm not sure about the LS engine there expensive up here and hard to find with manual gearboxes.

This turned into a free engine after I parted out the mustang.



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So far the engine is running pretty good starts so easy every time. However it is seems to stubble a bit once it warms up. I haven’t been able to take it for a test drive yet, waiting on new rear brakes and I haven’t got the temp and rpm gauge working yet. So I’m waiting on those to do a shake down run on it. 

This is how its sitting as of today.




Not a big fan of the intake I need to do something new there. But in the mean time for testing it serves its purpose.

I'm not able to fit the strut bar anymore so need to come up with something.



Edited by bimmota
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Ya I made that crack fitment issues, had to put it in the vise and bend it. Went a little to far I'm swapping that piece out for silicone hose soon ish here. But I have since tin tapped it made no difference. Apparently this issue haunts 99-04 mustangs when you go straight through exhaust, BBK throttle body and intake. I pulled the IAC valve all apart seems clean and working. I put the expansion black box back in for the IAC too no difference. Maybe it just needs a good burn run let the computer re-learn.


Cleaned a bunch of the wiring up today. Installed one of those inline rad hose temp sensors I like aftermarket temp gauges over stock but I will get the stock gauge working here one of these days. 


Yellowoctupus I noticed you used the hydro booster in your car was it worth it? I assume you have power steering? did you use the ford steering rack. I ask cause I have it all sitting in my parts car do I keep it before I scrap the car?



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Well took the car out for a test to burn this weekend. The engine seems to run pretty good the stumbling only seems to be during cold, once I'm out on the street idles just great. Need to wire the OBD2 port up next to pull codes.

Few issues: pretty sure I blew the seals in my new Wilwood pull slave cyl, brake fluid everywhere still holding the pressure tho, but leaks when I push the clutch pedal in. Need to come up with something new there.

The clutch slips pretty bad in 3rd gear and up it wasn't new but it is a center force stage 2, I haven't looked to see if the slave is releasing all the way or if the clutch is soaked in brake fluid.

And I bent the shift forks in the transmission it doesn't like to shift very nice anymore. Definitely not fault.


So the trans needs to come out for a rebuild.

It still moves pretty good with a slipping clutch


All in All I'm pretty happy mostly everything works for a 2 month build just going at it on weekends. 







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Looking good!  Yeah, so I went from no booster (or a bad booster, I should say) to the hydrobooster and the difference was huge.  At least pull the booster and keep the power steering pump (+lines) etc for now.  They do work really well, just in case you want to upgrade later, or if your stock vacuum booster goes on you.  And no, I never bothered putting in power steering.  I think the Subaru rack swap is very popular, as it's straightforard to swap.  It's been years since I've read up on it though.  Maybe I should look into it as I know my stupid bellows on the steering rack need replacing again.  (and I bought replacements but I've never been impressed with how their quality in the past).


Edited by yellowoctupus
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Thanks for posting!  I've purchased a DOHC 4.6 out of a 2004 Lincoln Aviator (300 ft-lbs@3250RPM, 302Hp @ 5750RPM) for my project, along with the ECU.  Basically all I want the ECU to do is control the fuel / ignition map and read whatever sensors it needs off the engine.  I'm going to bolt a WC T-5 to it, so the automatic transmission controls go away.  Pretty much everything from the firewall back I don't need.  To accomplish this I just need an SCT tuner with a custom program? And, of course, an appropriately abbreviated wiring harness.

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If your using an automatic engine ECU you will see the term PCM more often for fords. Pretty sure your going to have to trick the computer so that it reads neutral, could be wrong but something to research. Or source a manual PCM, I'm sure you can re program the auto out of the PCM.


You will have to supply 12v switched power to the injectors and coils the PCM doesn't have the power to do that. It works off grounding to firing everything.

You will need a OBD2 port installed to make an SCT Tuner work. Check out BAMA Performance for your tuner and email tunes. I used the mustang shop out of Calgary.

I took the easy route by buying a working car and putting the tune on it to delete everything before I pulled the engine, cause I knew I wouldn't get to the OBD2 port wiring right way.

Had to tare the dash apart to get that wiring. 04 I will assume it has PATS that needs to be disabled. And you may not want to keep the return less fuel system.


You can always send your PCM away to get everything flashed onto it as well one shot deal.

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