Looking at the options for either running isoflex or polyflex coupling between the Dana spicer 1410 universals
flange yoke/companion flanges on ski boat

anyone had any positive experience with these heavy duty ureathane couplers?

i was thinking might need a little give in the motor/gearbox
as was going to solid mount the engine

the following are the links, I'm assuming there are other manufactures offering similar products

i was specifically looking at the isoflx IFC 4700HT (High Torque) as has torque rating of 2100Nm (1550lb) in pleasure boat

http://isoflextech.com/wp-content/up...00-GA-Rev3.pdf

Poly Flex Group - Advanced Polymer Technology for Vibration Control - 547 Flexible Disc Coupling

I don't know about the brands you mentioned but these work good.

https://www.gcsmarine.com/content/dr...rs/drivesavers

Looks like my cruiser has something like that between the Vdrive trans and the shafts.
Interesting.

My hatteras has the same thing. Only made of steel...wonder how big a roll of duct tape you would need...

after some discussion ended up purchasing the Isoflex IFC 4700HT flexible coupler rated to 2100 Nm (1550lbs) torque, 2 days delivery, US$320, nicely machined even fits on the Dana 1410 male/female universal flanges
a few pictures fitting to drive and gearbox

some pictures of flexible coupling

Updated picture of the Iso-tech flexible coupling

https://photos.app.goo.gl/UiSHwwtxb2wyov1v2