Go Back > FAQ > Automotive FAQ

Search FAQ Search FAQ
Search Word(s):
Matching Options:
Search in:

351 swap into a Fox stang-- found by CrazyInBlack
The official 351 swap thread.

Information gathered was from ton of research, and actually doing the swap on a serious budget. Keep in mind though, You always spend more than you plan to. Its Murphys Law.

Ok, here we go.

You will ABSOLUTELY need a new oil pan and pick up tube. Sold by FMS through Summit, Part number: FMS-M6675A58 - $131.95

You will ABSOLUTELY need to obtain a 28oz. 157 tooth flywheel and 28oz harmonic balancer. You can find both of these on summit or from pre 1980 mustangs.
You will ABSOLUTELY have to change your intake setup. The 351 intake is wider. If you have a Cobra (gt40) intake or a TFS intake now, both companies sell just a lower intake for the 351 to match the upper intake you already have.

If you want to keep your A/C and power steering you need a new accessory bracket for the 351. FMS also sells this through Summit, Part number: FMS-M8511B351 - $49.95

The 351 will also sit a little higher than the 302 in which 302 headers may not reach the H-pipe. Many companies sell 351 swap headers for this application. I prefer the BBK ones through Summit, Part number: BBK-1511 - $219.95

You may or may not Need a coweled hood. It depends on how tall your intake/carb is, also what motor mounts you use. Most setups dont clear the stock hood, so be prepared to shell out some cash, or to have fun with a dremel.

You will ABSOLUTELY need a new distributor. The distributor is different from a 351 to a 302. You can obtain one from a 5.8 FI truck or from MSD. I believe it might be important to mention weather or not your engine is a rollercam or flat-tappet when ordering the distributor to insure you get the right Distributor gear.

You will ABSOLUTELY need a spacer for the crank pulley for proper alignment of the belts. FMS sells this crank spacer through Summit, Part number: FMS-M8510B351 - $34.95

You will ABSOLUTELY Have to drill your existing 302 heads. The reason for this is that the headbolts on a 351w are larger. Some newer aftermarket heads are predrilled for the 351, but most are not. This is not a difficult task. You simply need to drill out your existing headbolts to be a small amount larger. Take a 351 headbolt with you when your drilling so you dont Overdrill.

The swap requires all sorts of little miniscule items which you will need to get for your personal application. These items may/maynot include kickdown cables, Accelerator cables, Larger Headbolts, Throttle brackets, etc..
These items are not listed in individual categories because autozone carries all of these parts in stock. Just bring in what you need for your application.
And what I mean by application is that if I give a certain part # for MY holley carb throttle bracket, it will not neccesarily work on YOUR edelbrock. If you cant figure out what parts you need for these items, You are not qualified to be doing the swap.

If a part was not mentioned, it means it is not required for the swap. Yes its nice to have subframe connectors, and while most people will argue its a neccesity for this much power, it is not required. When doing the swap you can do many things on a budget (as I did) But remember to get the overlooked parts in conjunction with your new power.

Yes, having a 351w block is a prerequisite for the swap, do not forget this step! lol

Now, for those money saving tips

Using stock AC/PS Bracket
I was able to use the stock bracket, simply by using very large washers and various spacers. You just need a large selection of washers, You torque them down enough and you can get them to hold it just as securely as the FMS bracket. (pics below)

Using stock headers
Headers. If your cheap you dont need to get new headers. The stock shorty headers CAN be used. (I am living proof) All you need to do is hammer the tube on the drivers side nearest the steering knuckle. It will be tight, but it definitely can be done. You will also need to modify your H-Pipe. The way I did mine was I cut my collectors off the Hpipe, and bolted them to the headers. Then, I welded a pipe from the collectors back to the Hpipe. Would cost a max of 30$ at any local muffler shop to do. THIS WORKS. YOU DO NOT NEED AFTERMARKET HEADERS (although I reccomend you get them if you have the cash)

Aftermarket Headers for a 302 in regards to swap:
Havent tryed installing longtubes onto a 351w, But I would put money on the fact that it would not work without SERIOUS Modifications. The stock headers BARELY fit, so attempting to use non-swap longtubes will most likely be a loss.
I have seen other typical shortie aftermarket headers however make the jump into a 351 with NO modification to the headers at all. Apparently aftermarket headers fit in nicely. Just keep in mind that if you dont buy proper swap headers, you will HAVE to modify your Hpipe, Making it impossible to upgrade to swap headers in the future, But allowing you to use any 302 style shortie header that is for a non swap function.
Let me clear this up so everyone can understand easily.
long tubes - Not worth the time labor to install
stock - some header modifications neccesary, but works great aftermarket shorties - most fit like a glove, Remember you must mod Hpipe tho

Getting stock Gauges to work when going carbed:
They will work fine as long as you dont cut any wires. I know its tempting to remove all those ugly looking ECU wires, But leave them untouched untill the end. When your done with your engine swap, Just reattach the sensors into there respected locations on your intake.

Fuel Pump for carb:
Everyone says you have to get a new fuel line pickup and all this nonsense.
Let me clear some things up here. I have not tryed using the EFI pump with a regulator but it HAS been done succesfully. You will need a return line going back into the tank though, or pressure will creep up on you when your idleing.
I used a holley blue out-of-tank pump. To do this, Just remove the EFI pump from the tank (drop the fuel tank) And place a tube in place of the EFI pump. You are now using your existing pickup without the 130$ pricetag.

Electric Fan:
For some reason, My clutch fan stopped working, This is a excellent time to upgrade anyways.
Also, Go get a 3G alternator.

A final note:
You should realise that in most instances, when people are going to a 351 platform, They tend to add other performance parts with it. Keep in mind how much HP/TQ you are realisticlly putting to the ground, and remember to consider the outcome if you put over 350 WHP to your tranny on a launch.
This is here to server as a informative dish for the engine side of the swap, and may develop into more. If you plan on doing this swap right, You should absolutely have subframe connectors, a stronger rear end, and a upgraded transmission. Just be prepared to break more things. They dont call it fix or repair daily for nothing.

Here are some other part #'s
Oil Pan - Ford Racing P/N M-6675-A58
Oil Drive - Ford Racing P/N M-6605-A341
Flywheel - Ford Racing P/N M-6375-A302
Harmonic Balancer - Ford Racing P/N M-6316-C351
Crankshaft Pulley Spacer - M-8510-B351

Here are some relevant links to other 351 swap info. Just keep in mind that they all tend to contradict each other when it comes to doing things on a budget. (some sites say that using the EFI pump is impossible, this is not true.) Use the sites as a reference for part#'s and other information not yet available in this thread.

General 351 info
General Swap Info
EFI to Carb Swap
General Swap Info

----------------------------------------------------------------- -------------------------------------------------------------------------- -------------------------------------------------------------------------- ---------
Here is some other usefull info.

351W Conversions, Every Nut and Bolt

This Water Box was supposed to be Part II of How To Make Your Mustang Hook, but with the introduction of the new 351W Sportsman shortblock we have been bombarded with the same question from dozens of people: "What do I need besides the shortblock?" The traction trilogy will continue shortly.

We have been doing 351W conversions for a fairly long time and are a big fan of the extra cubes and additional strength offered by a 351W over a 302 or 302 stroker. Be sure to check out several stories in the Water Box Archives to understand why we like them so much. But we have never sat down and listed all the miscellaneous parts you need for a complete conversion. Usually people think all you need is the oil pan kit, a lower intake and headers. While these are some of the major parts, there are dozens of lesser parts that are just as important.

We have tried to list every single necessary component we can think of. While some of you may have sticker shock after adding up all the individual parts, it's important to remember that many of these same costs are encountered when building a healthy 302 or 302 stroker. If you already have a lot of money invested in quality 302 parts, a 351W may not seem attractive. But for those that do not have to take a loss on expensive headers and a ported lower intake, a 351W conversion may make more sense than a 302 stroker considering the extremely affordable $1695 price of a Sportsman Shortblock and the fact that it is several times stronger than a stroked factory 302 block.

The parts list below makes the assumption that a pair of quality heads, roller rockers, roller lifters, adequate fuel injectors, at least a 65mm throttle body and upper intake are already owned. You'll also need to hold on to your stock water pump and timing cover. If your 302 is pretty much a virgin, you'll need to buy these major components, but you would have to have done the same for a 302 build up. No one ever said that horsepower was cheap. Smokey Yunick once asked a customer "How fast do you want to spend?"

In some cases, you may be able to substitute other parts than the ones we have listed that will raise or lower the total you come up with. Also note that some of the parts are not necessary depending on your combination. An 86 - 93 conversion uses almost all the same parts as a 94 - 95 conversion, so prices will be nearly identical. Also left out of the equation are motor mounts that lower the engine a bit, while not absolutely necessary, they help provide extra hood clearance. HPM "drop solid" mounts are a nice piece and drop the engine 3/4".

Part Price
SVO Sportsman Shortblock $1695
Oil Pump $35
Oil Pump Shaft $15
SVO Oil Pan Kit $145
GT-40 351W Lower Intake $309
SVO 351W Dampr $269
Stock Type 351W Dampr (Brand New) $189
ARP 1/2" Under Cut Head Studs $139
Mac Shorty Headers $189
Mac Long Tube Headers $289
Correct Length Push Rods for Hydraulic Roller $85
Flexplate for AOD or C-4 $80
10.5" Steel SFI Flywheel - 28 oz balance $249
Air Conditioning and Power Steering Bracket $60
Power Steering Only Bracket $50
Truck EFI Distributor $189
Steel Distributor Gear $35
Modify Vortech/Paxton/Powerdyne Bracket $175
H.O. Fibertrends Hood with at Least a 1 1/2" Rise $385 + paint
Complete Fel-Pro Race Gasket Set $159
Motorsport or other Hydraulic Roller Cam $229
SVO Timing Chain Set $69
Magnecor Spark Plug Wires $69
Oil, Coolant $20 - $45
Labor to assemble 351W, R&R engine, tune $800 - $1200

We've tried to be absolutely as thorough as possible in listing all these parts. But depending on particular combinations you may still need one or two things. It's impossible for us to foresee everything with so many possible combinations.

So now you know what you're in for if you decide to take the plunge and install an engine that has a better rod ratio than any 302 stroker and offers the strength of an A4 block.

Now let's focus on 351W conversions. We've built and installed dozens of 351W's in late model Mustangs and the results are very positive. The 351W is the answer to many of the 302's weaknesses. Even a late model 351W block ('79 - present), which is the weakest of all 351W castings, is significantly stronger than any production 302 including pre '81 302 blocks. The blocks are so much more rigid than 302's that while trying to squeeze every last hp out of our 351W '88 LX at Maple Grove, we detonated the engine hard enough to brake 2 pistons. Breaking pistons may sound like a tragedy, but it showed how well the 351W keeps head gaskets in place, all we were using were Fel-Pro 1011-1's, they weren't high tech head gaskets. If it had been a late model 302 block, we would have easily blown 4 sets of head gaskets during the weeks leading up to Maple Grove.

The 351W also offers a more desirable rod ratio compared to a stroked 302. And let's not forget that a 351W can be stroked (but that's a different Water Box altogether). But perhaps the greatest benefit over a stroked 302 is the cost. A 351W shortblock directly from SVO is only around $1300. If you're looking to build a 351W from scratch, you should have no problem finding a good core at a salvage yard, and the final cost - using good steel rods and quality forged pistons will still be roughly the same as stroking a late model 302, but the 351W will be much stronger and more reliable.

Now you're asking, what are the drawbacks to a 351W conversion. Well, you'll need a cowl or other raised hood with a 1 1/2" rise, a new lower intake manifold, new headers, one modified front dress bracket, and a new oil pan which can be purchased from SVO with a pick-up for only $135.00. A 351W can also give away the element of surprise to suspicious onlookers, but the vast majority of people fail to notice the difference in deck height, especially with an EFI engine that has a lot of accessories, plumbing and wiring.

So, for the average enthusiast who wants more cubic inches without going broke, a 351W conversion is a better choice than stroking the inherently weak factory 302 block. Both will make approximately the same power, and cost roughly the same, but the 351W will be more reliable and much stronger, unless of course you opted for the A4 block. But don't misunderstand the purpose of this article. We are in no way saying that stroked 302's are unattractive, we've built several and all have worked out well. But when stroking a 302, we have always used Motorsport A4 blocks, so they're not a budget oriented project that the average enthusiast can undertake.

351w Swap Info.

Written by: Mat Peirce aka MAT88GT

This is an ongoing article and will be updated frequently. If you would like to see more questions answered feel free to contact me

Will it fit?

The deck height of a 351w is 9.480" for 1969-1970 blocks and 9.503" for 1971 and up blocks compared to the 8.2" deck height of the 302w block. This equates to a taller and wider motor. There have been many people who have squeezed 351's under the stock Mustang hood, but chances are at least a 1.5" cowl hood will be needed for the 351w combination. The motor mounts on 351w and 302w blocks are interchangeable.

Can I reuse any 302w parts on the 351w?

There are many interchangeable parts between the Windsor blocks. The 351w uses a wider intake than the 302w, but you can use a cobra upper with a 351w specific lower intake. Timing covers, water pumps, and several of the accessory brackets are interchangeable. You do need a FMS power steering and a/c bracket in most cases. Cylinder heads from a 302 can be used on a 351w block by drilling the head boltholes to accommodate the larger 1/2" 351w head bolts. The 302w fuel rail can be modified to fit the 351w by extending the rail crossover tube. Will my 302w balancer work on my 351w?

The 351w uses a 28oz/in imbalance that is the same as early 302's. You can use a 28oz/in 302 balancer on the 351w.

What is needed to use the serpentine belt setup from a 302 on a 351w?

The 302 alternator bracket can be utilized on the 351w, along with the reverse rotation water pump along with the air conditioning and power steering brackets. The crank pulley requires a 3/8" spacer available from FRPP between it and the balancer for proper pulley alignment.

What do I need for exhaust on the 351w?

Swap headers are a must for a proper 351w installation. There are many suppliers of 351w swap headers and matching intermediate pipes including: Hooker Headers, Hedman, BBK, Mac, and Kooks. Most 351's will benefit from a 1 3/4" primary tube size.

What parts are a must have for a 351w installation?

First, you need an oil pan and matching pickup to mount the 351w into the Mustang that will clear the K-member. Moroso, Miloden, Canton, and FRPP all make exceptional 351w Mustang swap oil pans. Note that the FRPP version is a 5-quart capacity design while the others are 7 quarts. Crown Vicorias and Grand Marquis also have a dual sump 5-quart oil pan that will fit the Mustang K-member. Second, an intake is needed. If you are using EFI Edelbrock and TFS make intakes for EFI equipped 351's. You can also use a FRPP Cobra upper with a matching lower, or a 351w truck lower with stock EFI Mustang upper. For carbureted applications there are many companies making 351w carburetor intakes such as: Edelbrock, Holley, Weiand, and Offenhouser. You will need a 351w specific distributor. MSD and EFI equipped 351w Thick Film Ignition distributors will work with the Ford EFI EEC. Any points, Duraspark, or MSD distributor will work with a carbureted combination.

What block should I use?

All pre 1994 factory 351w blocks are non-roller designs. Blocks produced before the early 1980's used a two-piece rear main seal. Ford trucks and vans produced after the mid 70's use a stronger rod design often referred to as 'Football' rods because of their football shaped bolt heads. 1969-1970 blocks had a lower deck height (9.480") and provide more compression from the factory. These early blocks also have a stronger thick wall casting design and are often thought of as the strongest factory 351w block. Keep in mind that all 351w blocks are considerable stronger than the factory 302w block. If you need an exceptionably strong 351w block design FRPP and Dart both offer aftermarket 351w blocks in many varieties.

How do I install a roller cam in my 351w?

The easiest way to use a roller cam in the 351w is to find a F4TE casting number block from 1994 and later F-series trucks and E-series vans. If you happen to have a block produced before 1994 you can retrofit a roller cam quite easily. The first option is using 5.0L hydraulic roller lifters, retention spider, and lifter link bars with a reduced base circle hydraulic roller camshaft. This method requires machining the lifter valley to accept the spider bolts. Second, Comp, Crane, and Crower make retrofit roller lifter that will allow the use of any off the shelf 5.0L style hydraulic roller cam to be used in a non-roller 351w block. Any flat tappet 351w-302w flat tappet camshafts will work with the correct corresponding firing order.

What vehicles should I get my 351w from at a junkyard?

Ford produced many vehicles which used 351w motors including, but not limited to, the following... Mustangs Fairlanes Galaxies Cyclones Torinos LTD's Crown Victorias Grand Marquis Rancheros Cougars F-series trucks E-series vans Broncos

4.6 to 5.4 engine swap in a sn95 . ---scanned and submitted by myillwill
This swap has been performed by myillwill with successful rewards. The following was what helped him along. If you have any questions please pm him here on the forums.

All times are GMT -6. The time now is 10:46 PM.

Powered by vBulletin® Version 3.8.2
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.