The Coupe gets a 3 speed!

Hood off and ready to start the engine removal

Over the past several months, I have noticed a sound when the engine was running, that I couldn’t quite diagnose. After looking up several different things on the interwebs, I determined that I was starting to have a failing torque converter in the coupe. Not exactly what I was wanting to find, but at least I knew how to fix it. Unfortunately, the only way to fix it was to pull the engine and transmission.

When I first set the car up, I was in high school, and had been driving the ’54 F100. It had a 3 speed on the tree, and I figured I’d just make the ’40 easy to drive and put an automatic in it. Since I upgraded from the 283 to a 350, back in 2002, I have regretted not going ahead and putting the 3 speed in it at that time. This transmission issue provided the perfect opportunity to go ahead and make the commitment to put my money where my mouth was.

Since we took a 3 speed out of Dad’s ’34 last winter, I figured I would just use the SM318 transmission. After running some numbers, and after talking with several folks about it, it was highly recommended to change that thought and put a Saginaw 3 speed in it.

The reason for the Saginaw, over the SM318, was that it had a synchronized 1st gear, and I had a few different choices on what 1st and 2nd gear ratio I could choose that would work better with the high 2.79 rearend gears that I had in the car. This transmission would also be able to be used with the stock column linkage, since it is side shifted. Other concerns about the SM318 was that it has a smaller diameter output shaft, and one transmission shop that I spoke with told me that most of those have a slight twist in them over years of use.

So…the first step was planning. I found all my stock clutch linkage in a box in the garage, and was planning on making an adapter plate to use a hydraulic clutch setup, using the bellhousing that we took off of Dad’s car. This plan was well under way, when a suggestion of using a Chevy to early Ford adapter, mated with an early Ford to Chevy transmission adapter. This would allow me to use the stock linkage! Unfortunately, it cause me to have a lot of measuring and investigating how successful it could be.

A couple of years ago, I snagged the Powerglide transmission adapter that came off the 283, and an early Ford adapter ring that were intended to be used in Dad’s ’32 sedan, and started gathering other parts that I would need. I had Doug order an Early Ford to Chevy transmission setup from Speedway, I bought a clutch kit from O’Reilly, and found a 3 ring Saginaw 3 speed. The 3 ring variety has a 3.5 first gear ratio, and a 1.89 second gear ratio. Perfect for what I was wanting!

A week later, I was bolting stuff together, measuring, and convinced I could make it all work. I scheduled a LONG weekend, before Thanksgiving, starting on the Friday prior, and figured I could get the car in Doug’s shop during a slow time, so I wouldn’t interrupt business there, and could tear it up and have it back together in a few days.

In the meantime, my ’40 Stake truck got booked for some photo shoots, so half of my Friday, and all of the Sunday were tied up with no progress on the coupe. That was all good, but the whole time, I was thinking about all the work that I had before me!

Since I am already long winded about the project, the short version is this:

  • The engine came out with a 350 turbo attached
  • The engine went back in with the Saginaw 3 speed attached through a series of adapters
  • The clutch linkage worked
  • The exhaust had to be rerouted to make room for the clutch linkage
  • The car came home with me Wednesday early afternoon!

Here’s a few pictures of what all I am talking about. Yeah, I did spend small amount of time cleaning all the oil off of the engine from the leaking valve cover gaskets and replaced them with some new ones.

And a cooler shot from over the hood

Ready to take the carb and distributor out to make room to pull the engine and transmission

Looking back at the empty engine compartment, maybe I should have taken a little more time to clean up that area.

Leaking valve cover gaskets sure did get things greasy!

Clutch pedal back where it belongs! That’s an original 1940 plywood toe board in that photo, too!

A quick peek to see the clutch linkage ball and see that there was no room for clutch linkage with the exhaust in the way

Saginaw transmission mounted to the Speedway adapter, to the Early Ford adapter, to the Powerglide ring, to the 350 engine.

With the engine out of the car, it gave it a gasser stance. Blocks under the wheels allowed for the engine hoist to be able to go in under the axle.

All back together, waiting for the shortened drive shaft and exhaust reroute. I even put on a new hood ornament to replace the broken one!


For reference, in case anybody is crazy enough to follow in my footsteps with something like this, here’s what I used:

  • SBC Powerglide adapter to early Ford (Just because that’s what I already had)
  • Speedway Part # 91628926 Early Ford to Chevy standard transmission adapter kit, including stock throwout bearing and sleeve
  • Old Ford clutch throwout fork and shaft, robbed from an old shelled housing that I had
  • A “Long” throwout bushing, due to the extra 3/8″ caused by the Powerglide/Early Ford combo
  • Clutch disc and pressure plate from O’Reilly K1675-10
  • Stock ’40 Ford linkage that I had removed from the coupe 30+ years ago
  • Saginaw 3 line 3 speed (due to it’s low 1st and 2nd gears, and my rear gears being 2.79’s)

NOTE: I did use a die grinder and took about 1/8″ off of each of the fingers in the clutch diaphram, to make sure that it would clear the circumference of the throwout bearing sleeve.

There’s a few things I need to work on to “complete” the job. I need to get back under it and adjust the clutch a little bit, and I need to make new transmission shift arms, clocking them forward at about a 45 degree angle, so it shifts a little cleaner, but right now, it’s working! All the planning and cypherin’ seemed to pay off and we only had to do the job once this time!

Now the “hot rod” SOUNDS like a hot rod when I shift gears and the lower first and second gears really make the car a whole lot more fun to drive!

If you have read this far, thanks! My family say that I ramble too much when I tell stories.

The FUN is in the RUN!!!