So I'm seriously contemplating a ZF swap for my truck, as I'm going to college next year, and will have to get on 75mph highways to get to home and back.

My local u-pull-it has great prices on transmissions, but I've never seen a ZF behind a 300 there, only 351's. All the searching I've done here has netted me threads dealing with a ZF from a 300 donor truck.

The 351 and 300 flywheels are balanced differently and won't interchange.
Is there any reason that I couldn't use my current flywheel?
I'm sure that the input spline pattern is different between the ZF and my current T18.
Could I just get the proper clutch friction plate for the ZF, and use my current pressure plate and flywheel (if they're in good condition)?


Since my clutch is currently mechanical linkage, can I install a new clutch master cylinder (with the firewall reinforcement) and use the current pedal, or do I need a complete pedal assembly from a hydro clutch truck?

I know I'll need to get the crossmember from the donor truck too. What else am I overlooking?

 

There are a lot of good write ups online, but, like everything else, it's all about the v8's. I can never remember whether it is the C or W with the small block. Of course it is the s.b. you want. All the research I did seems to say not to interchange any of the clutch, p.plate, f.wheel, OR starter. But I would keep your pedals, just install the hydro clutch.

Here is a photo of what you need, minus the pedals. The thing about the j/y trans is that with untold mileage, these trans can start losing their synchros.

Good luck.

 

I don't know if the input splines are different between a T18 and a ZF but I would guess that they aren't. I have an input shaft from a mazda M5OD that works fine as a pilot tool for the NP and BW 4speed clutches, same splines. So I'm guessing Ford probably specified the same splines and pilot bearing bore for the ZF.

 

A ZF from a 351W will bolt right up to your 300. As noted, don't use the 351W flywheel. The 300 flywheel should be fine. Most (maybe all?) are drilled and tapped for both 10.5" and 11" clutches. Either size clutch would be fine behind the 300, but I would prefer the 11 if you are buying new. You will probably have to move the transmission cross member a couple of inches for the ZF (not a big deal, just have to drill a couple of new holes in the frame. You may also need a different length drive shaft. There are several good threads on here about the swap including a lot of good information and pictures. Do a search and you will find lots of helpful stuff.

 

[quote=f100jim;10132680]A ZF from a 351W will bolt right up to your 300. As noted, don't use the 351W flywheel. The 300 flywheel should be fine.

Okay, I'm curious. Why would you not use the 351 flywheel? Is that so it will align/fit to the 4.9 starter?

Also, I've seen guys use the C6 cross member with a ZF, moving it back as stated, and with some modification.

And, can you guys clarify this for me? So the Cleveland 351 takes a diff. bell housing, right?

 

A 300 flywheel is for a 300 a 351 is for a 351. I think the 351 flywheel is externally balanced or something like that to make it different. The flywheel is engine specific for a manual trans. I believe they are weighted different.

 

And, can you guys clarify this for me? So the Cleveland 351 takes a diff. bell housing, right?

 

Correct. 300 is internally balanced, while the 302 and 351W are externally balanced, so these flywheels have a balance weight on them.

As for the 351C question, it uses the same bellhousing pattern as the 300/302/351W, but last saw US production in 74. 351M/400 use the 460 style bellhousing pattern.

One important thing to remember about the clutch, the disc has to fit the ZF splines, and the pressure plate has to be correct for the ZF throwout bearing. Wrong depth PP can really foul up the works......

 

One important thing to remember about the clutch, the disc has to fit the ZF splines, and the pressure plate has to be correct for the ZF throwout bearing. Wrong depth PP can really foul up the works......[/quote]

Thanks for the clarification, both of you. So, if say I pulled a ZF from a 351 W, couldn't I just order the entire clutch assembly, t/o bearing for a 4.9 with a ZF?

 

I would assume the clutch/PP/TOB would be the same for either a 300 or 351W. The flywheel would be the only difference.

 

I would just order the clutch kit for a 4.9l just to be totally sure. The bolt pattern on the flywheel may be different for 351 clutch.

 

Got me curious, so I went looking. Rockauto shows the same clutch kit for a 4.9L over 8500GVW, as it does for the 351W. Under 8500GVW shows a different clutch for the 4.9L, 10" rather than 11", sounds like the mazda trans there.
The 351W was not offered with the M5OD, only the ZF, unlike the 300 which had either depending on GVW.

Now, I'm not saying that rockauto's listing is 100% accurate, but it sure seems logical to me. In fact, I'd be surprised if the 460 used a different clutch than either a 300 or 351W with the ZF. I know the diesel does, but that's a totally different story......

EDIT: 460 does use a different clutch. 12" rather than 11". Learn something everyday......

 

You guys have saved me untold hours and $ when I get ready to do my ZF project. Thanks.

 

Unless you're starting with a 5-speed truck you will also need. Shorter in the rear and (assuming a 4x4) longer in the front. The ZF is longer than a T-18/19.

A 351w clutch set for the ZF bolts up and works with the 300 flywheel, no worries.

Replace everything when you do the swap - clutch set, slave/throwout bearing, new/resurfaced flywheel. Northern tool sells the slave hose release tool, fwiw.

Unless you're 100% sure the tranny is tight I'd take it in for a bench rebuild before I installed it too. The shift forks on mine were cratered and I ended up spending a few hundred extra bucks having the shop drop and reinstall the tranny after I found out my "like new" ZF was worn out...

 

Both points are what I had suspected, thanks!

One more reason to order the clutch for a 351W, the ZF was the only 5 speed found behind one, so it will much less likely to get the wrong one......