The first thing I did after purchasing the 41 was read everything I could find on the Internet and in the books that came with the car. The owner before Dennis was an older gent that had passed away. He had all the reproduction manuals for the car including the owner's manual, body parts manual, service parts manual, sales brochure and a thick, hard cover book on how to rebuild the 216 cu in 6 cylinder engine that is in the 41. I quickly realized the original drive line was great for shows and parades but not much good for driving any great distance or with any regularity. Turns out the 216 has Babbitt bearings in the rods and mains instead of insert bearings as is currently used. The 216 doesn't have a pressurized oiling system either. The bearings are lubricated by a "splash oiling" method whereby dripper tabs on the bottom of the rod caps pick up oil from the oil pan and "splash" the oil on the crankshaft. These engines do not employ any type of oil filter either. The transmission is a vacuum assisted 3 speed with a column shifter. The service and sales manuals refer to the 3 speed as synchronized but it isn't anything like the modern synchro systems with brass blocker rings. These old Chevies didn't use an "open drive line" either. The driveshaft is encased in a tube that is rigidly attached to the rear end housing like a long tube. The rear end floats a bit and this torque tube system keeps it in line. Because these old 6 cylinder engines didn't have much power, the rear end gear is quite high to enable torque multiplication in order to move this 3100 pound sedan. The rear end gear ratio is 4.11:1 and the engine with it's 1 barrel carburetor is rated at 90hp. The one in my 41 is actually a 52 engine and is rated at a whopping 92 hp!
I found several forums and web sites dedicated to the restoration of old cars or the building of customized hot rods and many references to the swapping of the 216 engine for a later model 235 cu in engine. http://www.inliners.org/Jack/t5_page.html http://www.stovebolt.com/techtips/engine_swap_216.htm The 235 is physically the exact same external dimensions as the 216 so swapping is easy. Further reading indicated the easiest way to get rid of the torque tube/4.11 rear end issue is to replace the rear end with one from a 55-57 Chevy. The lengths are the same with the later rear having a smaller bolt circle for the wheel bolt pattern. The 41 is a 6 bolt, 5 1/2" bolt circle while the 55-57 rears are 5 bolt, 4 3/4" bolt circle. None of the info I found discusses the diameter of the centering hub on the axles but that is certainly something to consider when making this swap. The other item to go from the stock driveline is the 3 speed transmission. The preferred trans to replace it is a Borg Warner T-5 5 speed w/overdrive unit originally used in the Chevy S10 pickup trucks. The shifter location on the forward part of the transmission tailshaft housing places the shifter just in front of the bench seat in an early Chevy sedan like mine. Another consideration is the speedometer. T-5s made after 1987 or 88 use an electronic speedometer system while the earlier units are cable driven like the 41. I found a chart showing the different T-5 part numbers and gear ratios and determined the most desirable one for me would be a 1985-86 unit with a 3.76:1 first gear. http://www.inliners.org/Jack/t5_page.html The one factor to this swap that made me gulp a bit is the need to cut or remove the existing transmission cross member and fabricate a new one to fit the T5. I didn't like the idea of cutting this original car at all! I wanted to approach any modifications with the idea that anything I did could be easily undone and the car returned to it's current restored condition. I also wanted to keep the existing look of the car with the 6 lug wheels and stock hub caps and wide white wall tires. So, I decided to let fate take it's own course. I would keep an eye out for the parts necessary to perform the driveline replacement but I didn't plan to run any ads or go out of my way to locate these parts. Little did I know how easily the needed parts would fall in my lap!
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