56ci OMC with 4 Spline Driveshaft

[Cubman]

I have a 1983 75hp Johnson long shaft with a jet pump. The motor has excellent compression but I believe the #3 rod is making a noise. I would like to replace the motor before it lets go. I have read that the 56 cubic inch motor is better suited for jets. If I find a 1986-1988 OMC 70hp it should be a 56ci motor and still have the four spline driveshaft so I can swap my pump on, correct?

 

[Lil' Blue Rude]

Yeah it should be. A new drive shaft only around $180 or so and it can be used with your old bearing carrier if you find a good deal on a newer model 56 with the fine spline crank. Some of the 86-88 60hp could be 56 cubes too, not sure. Only way to know for sure is to look at the heads. 56 has a one piece head the 49 have the 2 piece head with removable water passage cover.