Wonder if any of you out there has ventured into swapping from an old Pushrod Motor (460 CID) to a Modular Motor (4.6L) in a mid 80's F250?
I need to get rid of the tired old gas guzzling 460 and I have low mileage Cross-Drilled 4.6L Engine & Automatic Trans (not sure of the Model) from a wrecked 99 F150. Just not real sure on availabilty of parts for this conversion?

I'm not completely ignorant to the conversion world but most of my experience is in Ponies (64 1/2 to 93). My most recent venture was putting a GT40P into an 1982 GT T-Top Mustang. This required the installation of a Painless Wiring System and a Stand Alone Engine Management Platform. This retro didn't require any mods for the Trans as I stuck with the original SR-4 Speed (didn't want to spend the money for a Tremac). Also required some creative Exhaust work as at the time of the conversion there wasn't much marketed yet and the upgrade from a 7.4" to an 8.8" Rearend (Hp reasons).

So any suggestions or advice as to what I may be or need to look at for this one will be greatly appreciated.
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i think once you finish that swap you'll feel like you downgraded power wise

 

I'm not sure if a swap kit exists or not, however here is the way I would approach it.

The mod motor and trans was once managed by an EEC through a factory wiring harness - if you have those, the swap is far more simple, because you'd swap those in as a self-contained unit then attach power, ignition, and a couple of other things and you'd have most of it done.

The EEC does need a speed input, and if in your combination that comes from a sensor mounted on the transmission, you're good to go if you have that piece of harness. If the speed sensor was originally mounted on the rear axle, then you have some grafting/fangling/simulation to do and I can give you some ideas there if you need them.

Because your truck is very old, the cluster gets most of it's "data" from analog sensors - you can keep those in parallel to the 4.6L sensors (making "T" fittings as necessary), then you won't have to cut up your interior trying to shove in the new cluster and all that wiring - most likely.

Where there's a will, there's a way. Years ago I had a 75 Dodge Pickup, with a big block stroker (and a pair of turbos), GM ECM and homemade wiring harness, and a Ford E40D transmission (replacing the constantly breaking 4-sp manual).

I assure you, your swap will be easier ;-)

 

Yep, going from 460 cubes to 281 is gonna be a bummer.

 

Yes it will be a drastic reduction in power but that's ok as this Truck doesn't do any pulling, at least major anyways. It will probably just get used as a daily driver and occasionally a trip to the Hardware Store or Dump. I had also thought about an FI 460 but opted out because of cost related to Big Blocks.

I was already thinking about adding in the original Analog Senders and Switches but was curious as to what was going to be needed to use the original EEC, I mean as far as is there any other Chassis Sensors utilized or required in that. The other option would be a Stand Only Engine Management Platform but that wouldn't accommodate the Trans. I think I have enough information to feel comfortable proceeding with the Swap. Still any other input will be welcomed.

 

I forgot to add a couple of things.

I do have all the original Wiring and EEC from the Donor Truck.

I also believe a lot of the power shortage can be overcome with some readily available Bolt-On Power-Adders.

 

There are no power adders to add to a 4.6 that can make a 7.5 out of it.
Maybe a turbo charger with 20 PSI of boost would work for 20 minutes or until the tranny was put in gear.

 

Guys,
I don't nor have I ever believed that a 4.6L would equal up to a 7.5L, the ability to produce and maintain torque comes from rotating mass and cubic inches. Neither of which is in the 4.6L. I think in my stash of parts I probably have everything needed to Twin Turbo it but it pop like a bottle rocket, I would be better off with a small Twin Screw (Bolt-On thing ya know).
I just thought someone out there might have already done this and could offer some pointers on parts, outcomes and possible solutions.

 

Well I mean, depending on how much you wanna spend obviously you can make whatever power you want out of the 4.6L. But at that point you aren't going to be getting any more mileage out of it than the 460 are you =P

 

You could probably get some decent performance from a 5.4L as there are many performance upgrades available for the engine.
The 4.6 can be made to get some good HP but not too much for torque. In stock form, the 4.6's torque feels a bit gutless in the sedans and trucks but feels like will almost rev to no end.

 

I see a whole lot of work for not much gain.

The 4.6L powered trucks get (realistically) 13-15mpg and are notoriously doggy. A 460 gets 8-10, and will pull a house sideways. You're going to take out an (I'm guessing) dependable motor to replace it with an electrical nightmare? No thanks, if I'm going to suffer through a 3/4ton's lack of ride quality, that pig is going to be able to do what its intended for, not be a psuedo-gas sipper.

Probably not the response you're looking for, but you asked.

Edit: Just thought of this, but the 4.6L trucks are also considerably lighter than an 80's model F250, and considerably more aerodynamic. You're stacking the deck against yourself at every turn in this proposed build. I just don't see this idea being near as effective as you've built it up in your mind.

 

A Quad Cam 5.4L would be my first choice but I have a Truck 4.6L and Trans. I'm hoping that later down the line some of the low torque can be overcome with the right Gears and a High Stall Converter, taking advantage of the Rev'ing abilities of the Mod Motors.

 

Although I would not do this swap myself, it's not totaly dumb. The F250 came with a 5.0l in the 80's and 90' and a 4.6l in the 1998 lightduty F250. The 5.0l has 185hp 270tq and 4.6l has 220hp 290tq and with PI heads 231hp 293tq. Seems to me that would be enough power to do the light towing and whatever else. If the tranny is a 4r70 or 4r100 then you should be good.

I seen on another forum a few years back, a guy put a 5.4l into a 1978 Bronco and he also swaped over the dash and interior. He got a a lot of crap for it but I thought it was pretty cool.

I say you go for it. I don't think it would be all that hard.

 

I have an '01 CVPI with the 4.6 and it does not feel like it has that much torque. It feels like it loses steam going up some hills.

 

Use motor mounts from a '99 Mustang and cut or mod your existing perches to take the mounts. I put a 4.6L in my Bronco in place of the 302, I had to fab some plate steel on top of my perches to raise the mounting holes, but the 460 uses 2 holes per side, one high and one low, you might get lucky and be able to fit to the top hole.

The problem with the exising harness is that the ECU goes on the passenger side on the '99 and on the driver's side on the older trucks, so everything is backwards.