Technical SMOD 3+1 to Early FE 352

Hey y'all,

Lurking through here, I've been reading a lot about the 'imposter Toploader' 3+1 SMOD trans with cast iron case. I see a few for sale, so it's getting the wheels turning.

I have a '59 352 block in a '58 Mercury. Car currently has a Cruise-O MAX bolted in. This seems to be an easy answer to my overdrive search. Despite all the reading, I've still got questions. I was reading somewhere about fitment issues with early applications, different shaft sizes, having to cut the tunnel under the seat, so forth.

I saw a lot of references to a Hurst shifter that's getting hard to find. Is the stock one really that bad of a throw for a weekend cruiser?

So I'm hoping y'all could give me some ideas what all I would need and what to look out for to get this into my '58 Merc body behind a '59 FE. Fabbing a cross member isn't an issue, and a driveshaft will be custom made after the fact.

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For a weekend cruiser it would probably be an acceptable replacement for the Cruis-O. I would think it would fit OK, rework of the trans crossmember should be expected. The shifter position could be problematic. The other thing to worry about would be your rear end ratio. A ton of those late 50's and and early 60's Mercs came with 3.0 rears. That could be a bit steep with an OD, even a small ratio OD like SROD at 0.78.

 

Pay attention to which one you buy; some (notably the truck versions) have a really poor gear spread (BIG jump from 1st to 2nd) that you may not care for. The car units have better ratios.

The stock shifter can be 'upgraded'. Ford used a rubber bushing on the lever than tends to wear and get sloppy, making for indeterminate shifting. Replacing that with a bolted connection will help considerably (some fab work required). The other issue is some factory shifters have a nylon 'block' sandwiched between two steel plates as the 'selector'. This also wears, but can't be tightened up because the assembly is riveted together. I drill out the rivets, enlarge all holes to 3/8", then reassemble using long 3/8" bolts with nyloc nuts so you can adjust the tightness. I also drill it for a grease fitting. You can improve the shifter quite a bit by doing this. It still won't be a Hurst, but can be the equal of the original OEM four speed linkage, which wasn't bad when adjusted right.

You'll also need a '65-up FE clutch/flywheel/bellhousing/starter for the correct trans-to-bell bolt pattern and front retainer bore size, and need to trim about 3/16" off the end of the pilot shaft on the trans input so it won't bottom against the crankshaft. This is if you use a car bellhousing; the truck bell is deeper (and may require some firewall bashing), no trimming needed but you do need to make sure you have full engagement of the pilot shaft in the bushing. If you don't, switch to a steel sealed bearing for the pilot, it won't 'hog out' with partial engagement like the bushing will.

 

Steve brings up some very good points.

More food for thought: By the time you are done re-working flywheels and clutch plates, adding in a clutch pedal and linkage, chopping your floor up for a shifter, and re-building a 30 year old trans, you might be better off ordering an AOD from Broader Performance or Lentech with your Cruis-O bellhousing grafted on. It will cost you $2500 to $3500 depending on options, bells and whistles, etc. But the SROD conversion could easily nickle and dime you out of that much cash by the time it is all said and done.

Fact of the matter is, there is rarely an easy and cheap route to putting a modern OD behind an FE. The only OD the factory ever install was the Borg-Warner R11 unit bolted to the back of T85 3-spds.

 

I can't imagine a toploader conversion would be all that expensive if you can get the trans at a reasonable price. How difficult it will be rounding up clutch linkage is another story....

This isn't a hard swap, but you do need to pay attention to the details. The main drawback to the toploader overdrive is OD is actually 3rd gear, so heavy loading in OD is hard on the cluster shaft/shaft bearings which really weren't designed for this kind of service. I know in the truck applications, Ford DOESN'T recommend using OD if hauling a load or towing. So that's something you want to check on a used box. And with taller rear gears (like 3 flats), the OD will be useless anywhere except the freeway. A 3.25 or 3.5 gear will put you in the 'sweet spot' for the OD.

 

Definitely appreciate all the info guys. In talks with my buddy to see which way we want to go. Car was originally a manual, so we have some clutch parts that could be used if we went that route. We're running into issues converting the standard column to work correctly with the MX. It's a double edge sword at this point. The manual would probably be easier to get in, but I'd need to source all the parts and spend more $$$. We have most everything for the MX, just a matter of fabbing things to work with the column, like a detent plate and safety switch.

I'm unsure of what rear is in the car, I haven't referenced the codes, but I'm guessing the 3.00s. I wouldn't think they'd be too bad on the highway. My '88 Grand Marquis uses the AOD and has 2.73s in the rear and works fairly well above 45mph. I run a lot of highway and have a 70 mile commute to work that just begs for OD...but now knowing I can get an FE AOD down the road hasn't help my decision!

 

I have a toploader imposter in my 58 Ford Custom behind an FE. Trans was from a late 70's van. I had no issues bolting it all together and did NOT modify my trans crossmember or tunnel (besides the obvious hole for the shifter). I just modified a trans mount to bolt to the stock cross member.

Been running this combo for a few years and originally had the stock SMOD truck shifter in it(the van shifter didn't work as the mounting bracket put the shifter too high and into the floor) and it worked fine but felt like a Mack truck going through the gears. So I adapted a hurst shifter to the stock trans shifter bracket and worked out with a little tweaking of the shifting arms.

My car was originally a 6 with column shift and I did have to modify the zbar as well. Rear end is 3.22 I believe and cruises at 70 mph right around 2k. The rmp drop from 2 to 3 is big but it's a compromise I'm ok with.

Is it just adapting the column shifter that's the issue with the FMX? Maybe ditch the column shifter and go with a floor mount? The auto shouldn't be too bad with a 3.00 rear on the highway and might be easier than re-installing the clutch linkage/pedal.


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The biggest issue is making it work like a proper automatic. We're trying to figure out if we can use a detent plate from a T-Bird or something like that. Going for a stock look if we can, floor shifters on autos just look tacky to me. If there's gonna be a stick there, it's going to be a manual.

Then there's the neutral safety switch we haven't figured out yet either...

- 1958 Mercury Medalist -