I got the overdrive about four years ago via eBay. I can wave to people as go around corners! Plus, the overdrive makes it easy to downshift without double clutching. 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. So, does the new setupВ work? Oh, yeah-I say with a big smile on my face. That set up works very well for my purposes.ДЄnother tip: I put Lucas transmission oil additive-the stuff that you see on the car parts counters-into the non-synchro transmissionВ and it worked so well that, for most of the gears, I can shift as if the transmissionВ is synchro. A sensor connected to an Arduino, to read the speed and drive a little electric motor connected to the speedometer headвЂ¦ IвЂ™ll probably use a GPS to provide the speed signal.Д«TW, 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. The truck cable housing wasnвЂ™t long enough to reach and the knurled connector didnвЂ™t fit. My biggest issue was with the speedometer output shaft. Simple! (an aside: make sure that the overdrive isn't engaged when putting the truck in reverse) Ran a 12 volt wire to a fuseВ andВ button mounted below the dash-and added a pilot lightВ that shows when the overdrive is engaged-and that was it. I fitted an aluminum plate with an oil sealВ for the front end of the overdrive unit. 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. These are often listed on ebay-without the front drive shaft. The Laycock overdrive is common on older Volvos. That wasnвЂ™t such an issue-the tank needed to be replaced, anyway. I also had to move the gas tank over by about an inch to fit around the overdrive. It is important to mount these with the correct angles toВ preserve the u-joints. I installed two drive shafts, one from the to transmissionВ to the overdrive, the second from the overdrive to the rear end. 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. After doing a few calculations, I realized that the rear end would make the underpowered engine even more so. I wondered about switching out the rear end-and had picked up one that was a 2.80:1 ratio. 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. Gear Vendors sells aВ unit, or you can opt for the route I followed: findВ a Laycock J-type from a donor Volvo. No modifications needed for the parking brake, transmissionВ or engine. c- was the option that I was most interested in. and what aboutВ 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. The problem with a- is that the engineВ 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. Along with brakeВ upgrades, wringing more horses out of our flatheads, adding seatbelts and tightening up our suspensionВ 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-В 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. 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.

Laycock overdrive service manual