Mercury 500 15" shaft

[reelfishin]

I picked up a boat today with a 20" transom, but it has a 15" motor hanging on it. Does anyone know if a 15" Mercury 500 can be converted to a 20" shaft length?
I'm doing a motor swap anyhow, but would have more uses for this motor if it were 20". Even my smaller aluminum boats have 20" transoms.

[OldMercsRule]

Probably not worth the cost to add a section. I bet the motor is not new. Sell it to someone with an older 'short shaft' boat or buy one yourself and hang it on the proper boat. JR

[reelfishin]

The motor is super clean with good compression, the only bad is another stuck Merc Prop. It don't look like it's been used much. Someone started to rig it on a trihull, both the boat and motor are pretty clean, especially for their age. The motor came from freshwater as well, so it's not all pitted. It's got some minor paint loss, but mostly from handling. I've only gone so far as to make sure it runs, but all seams fine so far. Some minor touch up paint here and there and a fresh prop, it'll look nearly new.
It's got almost 150 lbs per cylinder, in the top 3, and I have no reason to doubt the bottom one, but didn't have an adapter to make the bend for the lower cylinder. The last owner bought it from an estate sale, but got the motor and boat separately. I take it that he knew very little about boats, and got frustrated when he found out that the two wouldn't work together.
I could make a motor plate, but I have a matching motor for the boat. I guess I'll set it on a stand until something come along.
Did they make spacer? Was it oem or an aftermarket deal?
I had a Merc 500 long shaft but just sold it.
I don't remember that having a spacer?
I can't remember the last time I found a good 15" tansom hull that would handle a 50 HP, let alone one this old or heavy.
I have two aluminum hulls here, both are 15' with 20" transoms.

[agitator]

Pretty raunchy looking prop ya got there too. Not much lost if you cut it off.