Re: 1979 Chrysler Charger 140hp lower leg help/ideas...
You can use any leg that has the same drive shaft length as yours (Chrysler DID make a 25 inch X long shaft and Force made more of them). Determine if your engine is long shaft (20 inch) or X long shaft (25 inch). Count the bolts on the bottom kingpin cap. 4 means 20 inch and 8 means extended shaft 25 inch.
You can use any lower unit from any three cylinder or Four cylinder Chrysler from 1979 on. You can use any lower unit from any Force three or four cylinder engine EXCEPT 70 and 75 HP up to 1994. You can use single exhaust or dual exhaust models. IF you us a later lower unit with the 1.92 to 1 ratio gears or an earlier 2 to 1 ratio lower unit from an 85 or 90, then you probably will need to go up 2 pitches on prop--ie. 17 pitch to 19 pitch. If you use a dual exhaust model, you will need to buy a through hub exhaust prop.
If you buy a newer lower unit with a two piece drive shaft (dual exhaust, for example) be certain the the shaft and coupler comes with it. They are difficult to find and very expensive. Again, if you buy a newer unit, be certain the water pump comes with it. Same thing, very expensive.
