1982 Carver 3607

For an exact replacement, model AND serial number will be required at a real Crusader shop.
Gear drive or chain drive helps determine the rotation. Pending the clutch and rotation, counter rotation engines may end up on either side.

For another option, When I worked on Chevys, I had a local cam shop that would custom grind, and repair cam shafts.
Also checked and match the cams on the twin engines.
Amazing what errors we would find after others worked on some engines.

I found this web site for giggles.
https://bpi.ebasicpower.com/shop/crusader-inboards/engine-system/camshafts

Good luck

Could be a hunt;
It looks like; Pleasurecraft purchased Crusader from Thermal Electron. (When you can't compete, buy your competition)
Since they already had a line of engines (PCM) but still wanted an extra share, They cast them out as another engine group called Challenger.
Here is a dealer locator page.
https://challengerengines.com/dealer-locator/
Looks like a couple of dealers in NY. Call them for a closer shop and better details on my assumption above.

Keep us up on your projects. We like to watch..