With the wrong gearing, you have to drop down in pitch on the prop. If your current prop is a 21 pitch, you can drop to a 15 or 17. However there are not props below 15.
I would get the right gear ratio
Use summit racing website to get part number. Then Google around. Summit will match prices. When I get home, I can look up part number. (I think there is a pic of the box in my build thread). Currently at doc office
here is what your $6k is buying.
$2k worth of remanufactured motor and $4k worth of labor
or
$4k worth of crate motor and $2k worth of labor
if you want to lower the costs, you will have to do the work yourself
neighbor has the grid in his yard for his RV. that is one option, however you are still trying to push a boat on land
I used to use my lawn mower like mentioned. a 17hp john deer that I added a mount for my draw bar. it would move the trailer, around the yard, however the brakes were iffy...
watching you tube videos does not make one a mechanic
you have a volvo penta AQ260 (350 cubic inch V8 with flat top pisons, holley 4160 carb) which would have had a pertronix distributor
that someone put an older distributor on it from a car as others stated, a bomb. or someone replaced the...
pull the drive, split the case.
you most likely have a failed water pump. especially if it was packed with mud and water, it may have froze over winter.
other potential sources are a bad ball gear seal.