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A lot of us want to keep our trucks as original as possible and, at the same time, improve the safety and performance to drive comfortably on today's roads. Along with brake upgrades, wringing more horses out of our flatheads, adding seatbelts and tightening up our suspension components, many of us have asked--how can I cruise at 65 while keeping the RPMs in a decent range? The three "big" solutions that stand out are a- swap transmissions for something with an overdrive, like a T-5 or an A833, b- swap rear ends, or c- add an overdrive, such as a Laycock. The problem with a- is that the engine may need to be pulled, an adapter plate might be required, a new hole in the floor must be cut and then there is the clutch... and what about the parking brake? The second option, b- presents the problem of gearing that is too tall for the torque output of the engine, especially if the flathead is wimpy, such as a 201. So... c- was the option that I was most interested in. No modifications needed for the parking brake, transmission or engine. Gear Vendors sells a unit, or you can opt for the route I followed: find a Laycock J-type from a donor Volvo. Here are the modifications that I did: The old truck came with the factory optional, slightly more desirable 4.10 ratio rear end (as opposed to the 5.63 stock rear end), so it could putter happily at 45 MPH and, sounding like a manic sewing machine, hit 65 MPH. I wondered about switching out the rear end—and had picked up one that was a 2.80:1 ratio. After doing a few calculations, I realized that the rear end would make the underpowered engine even more so. Maybe an overdrive would be better? I began a search that led to a Laycock model J overdrive, about the size and shape of a small watermelon. It fit nicely in mid-frame. I installed two drive shafts, one from the to transmission to the overdrive, the second from the overdrive to the rear end. It is important to mount these with the correct angles to preserve the u-joints. I also had to move the gas tank over by about an inch to fit around the overdrive. That wasn’t such an issue—the tank needed to be replaced, anyway. The Laycock overdrive is common on older Volvos. These are often listed on ebay—without the front drive shaft. I found a complete one, cut off the end of the shaft, and had a local machinist weld a u-joint receiver onto the end to accept a short drive shaft connection to the transmission. I fitted an aluminum plate with an oil seal for the front end of the overdrive unit. Ran a 12 volt wire to a fuse and button mounted below the dash--and added a pilot light that shows when the overdrive is engaged--and that was it. Simple! (an aside: make sure that the overdrive isn't engaged when putting the truck in reverse) My biggest issue was with the speedometer output shaft. The truck cable housing wasn’t long enough to reach and the knurled connector didn’t fit. I am working on an alternative, though. A sensor connected to an Arduino, to read the speed and drive a little electric motor connected to the speedometer head… I’ll probably use a GPS to provide the speed signal. BTW, in the process of putting the overdrive in, I discovered that the parking brake drum had developed a number of fractures and was close to exploding into fragments, so I replaced the whole arrangement with a snowmobile mechanical disc brake. That set up works very well for my purposes. Another tip: I put Lucas transmission oil additive—the stuff that you see on the car parts counters—into the non-synchro transmission and it worked so well that, for most of the gears, I can shift as if the transmission is synchro. Very nice. So, does the new setup work? Oh, yeah--I say with a big smile on my face. Oh, yeah, it is very, very cool. My 201 has no problem running the overdrive, and as a side benefit, I get an extra gear in 2nd and 3rd that makes puttering around town a lot more fun. Plus, the overdrive makes it easy to downshift without double clutching. I can wave to people as go around corners! Here are the pictures: