Thread size and ratio question
 

Anybody know the thread of the Bravo oil vent bung?
Looking to fit an external reservoir or where can I get a right angled barbed fitting to screw into the oil vent.
Also from the gear set "c" 883479 69680BX.
Is this a 1:65 ratio?

Thread size is 3/8x16. That is a 1:65 gear

Thanks,
Going from a 1:5 Bravo 1 to a 1:65 what difference in prop pitch would there be.

If say running 5000rpm with 1:5 gears going to 1:65 what would be the difference in RPM?
300?

303 slower to be exact.... you’ll need to go up at least 1 prop size maybe more, if you were in the low side of the top rpm range with the 1.5 1 size will probably be right

Does that mean I would be seeing 5300 RPM?
I need to find 300 to 400 RPM so going from the 1:5 to 1:65 may do it?

From the best of my knowledge, an oil vent adapter fitting comes with the kit!

.
no, that’s prop shaft rpm, if you were running 5000 rpm with the 1.5, you would need to run 5500 rpm to produce the same propshaft speed as the 1.5, but if the engine is capable of running the additional rpm it may pull even more rpm due to the additional torque multiplication ( it’s easier for the engine to turn that prop)

I have 2 late model 1:65 ratio top boxes.
I need to find 400 rpm.
Would it be wise to swap the 1:5's I have now,keeping the same props or are you saying that
will give me too much RPM?

If you switch to 1:65’s and keep the same props, you’ll most likely be over the 400
rpms you’re looking for, you’ll probably need to go up 1 prop size