Super Jet 650/701/760 same crank? Converting 650 to 760

[rambo22]

As of now I have a 650 motor in my sj, I was planning on putting in a 701 but then thought about a 760 because i believe the crank on the 650,701, and 760 are the same so why couldnt i just convert my 650 to a 760 with a cylinder change?

 

[waxhead]

The cases are different as well and make more power.
You could with work and machining put the 760 cylinder on but you would have to take the cases apart.
And since you have done that you almost there to putting decent cases on it

 

[kevbo]

The 650-701-760 cranks are dimensionally the same and will interchange. Installing a 61X cyl on 650 cases is a good mod for the $$$, this was popular when 701 first appeared. Inspect your crank before you do anything!! The 650 cases will need to be hogged out slightly to clear the sleeves. High port 62T and 760 cylinders will work but require more tuning experience to get running well. Single carb 701 cases are cheap and need no machine work, dual carb 701 cases are expensive. There are several easy options depending on your budget.