The original 32 Chevy passenger cars had a "FREE-WHEEL" device, when ingaged it would coast when you let off the gas, this was used in most American Passenger cars in 1932-1933,I heard of stories of a 1933 Chevy hitting 85 mph down hill ,the man that told me about this[said he was young and foolish at the time] was going on that long hill into Utica,NY ,now route 12, when he met two trucks one doing down hill the other going up! some how he got by them at the bottom of the hill he disengaged the free-wheeling never to use it again, I believe it became against the law to use them.
It could be used in your 49.
Chrysler with Borg-Warner, design the over-drive for the 1934 Air-Flow, and later it was used it Chrysler's that had the floor shift. GM was slow to use the O-D's there where some after market over-drives available for Chevies, in the 40's I almost think one showed up on this sight for sale.
