Hello, I have twin AQ170's with volvo 280 outdrives. I went through the motors that have not been on the water in many years and with the help of some new stuff got them running what i thought was well until i hit the water then neither really wanted to run well or right. I know the history of these engines and parts and such. I have a whole other spare engine as well. These motors have a little over 500 on one and 600 hrs on the other. I am at an impass as to what to do with this boat this winter. I am debating getting these running but between the three carbs and the distributor i am not sure if i want to continue to mess with it.
I can't say as I blame you.
I am thinking about repowering with a chevy 4.3l due to the abundance of parts. Anyone have an idea as to what would be involved to do this? Obviously the exhaust has to be redone and possibly the mounts but what else or is it even possible?
For one thing, the engine mount stringers would need to be re-done as to accommodate the side engine mounts.
See below as well.
What power plants will bolt directly to a 280 outdrive without a bunch of making things work? Any info would help. Thanks in advance.
Most any engine that Volvo Penta used (in the AQ series), will work with a 280 drive.
If you are not after speed, any of the OHC 4s would work.
If you are after more speed, then you would want to use the 4.3L or 5.0L or 5.7L GM SBC.
The 335 series Ford (302 or 351 W) would also be a candidate.
However, you would need to check the center-to-center dimension between the stern drives for a V engine, since these engines will require a greater distance due to the width of the engines.
For a V engine, (since you have the single exhaust relief transom shields), and only if the center-to-center dimension allowed, you would need two of the AQ200B or AQ225B exhaust Y-pipes.
The 280 transom shield will allow the use of any AQ series flywheel cover (bell housing in the auto world).
Also, for a V engine, the lower gear unit would change from the 1.89:1 to the 1.61:1.
For the OHC 4, the lower gear unit would change from 1.89:1 to 2.15:1.
I would start with the center-to-center dimension.