Frank Acampora
Supreme Mariner
- Joined
- Jan 19, 2007
- Messages
- 12,004
Those of you who are long time members of the forum will know that I tend to try and prove to myself "things" that have been told to me. I swapped a one piece lower unit and midleg onto an older two piece lower engine and proved that the one piece is indeed about 3 MPH faster as Chrysler claimed in their advertising.
I have in the past been told that the dual exhaust lower unit was developed to produce more power from Force engines--well, we shall see on Monday. Original lower unit was a 2 to 1 ratio and the dual exhaust is a 1.92 to 1 ratio.
Meanwhile to answer the questions "How can I tell if I have a dual exhaust?" and "What lower units will fit my engine?" here is a 1990 to 1994 series dual exhaust lower unit. Note the position of the water pick-up holes just above the gearcase torpedo.
Note also the distributor on the Chrysler engine. This engine is around 1978 to 1979. Since the midleg was not drastically changed until after 1994, this shows unequivocally that if the drive shaft length is correct, ANY lower unit from a three and four cylinder engine, 1979 through 1994 will swap onto any late model Chrysler and any Force up to 1994. (with the exception of Force 70 and 75)
Although the water pump and cover plate assembly is different and larger, this dual exhaust lower unit with a two piece drive shaft bolted on with absolutely no modifications. I used the original white exhaust snout --just because. It was handy and I didn't want to look for the black one.
