View Full Version : 351W swap article

04-12-2006, 10:41 PM
ill try to make this as informative as possible, although i suck at explaining stuff.

Unique parts you will need to acquire. These do nto account for the internal parts that are unique. (oil pump, rotating assembly, pushrods, etc)

Oil pan, a 302 pan wont work. any 351W swap pan for a Fox body Mustang will work. You can also get a replacement one for a 351W Panther. Auto Zone sells one for $80.

Intake. For a carb motor there are a good many choices for intakes. Edelbrock makes at least 4 different one, Ford Racing makes one, Im sure Weiand makes a few. For Fuel injection, you can either go with a truck lower, which might require the use of a truck upper. (i.e. hood wont close) Edelbrock makes 351 lowers that use a 302 uppers. Trick Flow might also.

Distributor. The 351W uses a 5/16" oil pump drive while the 302 uses a 1/4" drive.

Exhaust. If you use shorty 351 headers they should bolt up in the same location as the 302 shorty headers. However if you use 302 headers you will most likely have to have the exhaust modified to reach up to the collector.

Parts that are a direct swap.

Heads. heads are the same, except 302 heads will have to have the head bolt holes enlarged to clear the larger 1/2" bolts.

External parts. Valve covers, timing cover, water pump, pulleys.

Accesorys. the alternator and power steering pump and brackets are the same between the two motors, the belt is the same also. Im not sure on the A/C and smog pump, since i did not use those. (any one with a factory 351 car can you compare your brackets with a 302s?)

Motor mounts are the same.

Balancer and flexplate are the same provided your 302 is 28 oz. balance.

Coolant hoses are the same. the bypass hose form the water pump to the thermostat housing swaped from my 302 to the 351. I had to re-use it since the parts store did not have one.

issues i encountered

Hood clearence should not be a problem unless you have a tall set up. My 351 with an Air-Gap intake, Holley Double Pumper carb, 1/2" air cleaner riser, and a 14" Moroso air cleaner needed the hood bracing "modified" slightly, you have to use a nut not a wing nut. With a 1/2" nitrous plate under the carb the hood would not close. The Moroso drop base air cleaner required the 1/2" spacer because it would hit the float screws before it sat flat., with the 1/2" spacer the air cleaner was way too high. With a 9" air clener with a shorter stack heigth, the carb stud sticks out of the hood.

As for fuel injection i have no idea for hood issues.

Tall valve covers. I have a set of tall cast aluminum valve covers, I had to break out the entire bottom of the windshield wiper arm box for the covers to fit on. Even now removal is a very tricky process. go with the shortest covers that will work for you.

04-13-2006, 12:25 AM
Thanks for the info mang. It'll be useful for someone!

Sticky because it deserves it. I guess this can get moved into the archives at some point.

04-13-2006, 12:56 AM
Might want to add that all 302's from what 79 or 82-up aren't 28oz...

Sure about the oil pump shaft? I'd think the length would be different, notthe diameter. I distinctly remember using a 5/16 socket to prime my 5.0's..

04-13-2006, 06:21 AM
When I did my carb swap I retrieved my pump shaft (it had slipped out of the stock distributor) with a driver, I think those use 1/4 inch bits, right?

Grand Marquis GT
04-13-2006, 06:36 AM
Some are 5/16", some are 1/4"...

04-13-2006, 11:15 AM
Might want to add that all 302's from what 79 or 82-up aren't 28oz...

Yup. Most sources cite 1982 to be the year of change, although I've never figured out exactly what 1982 is, 28.2 or 50 oz. 1981 and earlier were 28.2 and 1983 and later were 50 oz. I remember something about 164 vs 157 tooth flywheels/flexplates, but I don't recall much about it.