Need you guys help on this one. I have never been in or around an inboard boat just i/o and outboard. I found a set of carbed 502's to repower my boat and they were previously set up for inboard. They said additional $250 to convert to I/O. What all does that involve?

First 3 questions:
1) What kind of I/O, Bravo, TRS?
2) Are you sure one engine is not reverse rotation?
3) What's included with the engines?
Gary

unless ones a reverse rotation like Gary said i dont think there should be any problem with the swap....any parts you may need should come right off your old setup...

I'm going to assume you're using a bravo.
Be careful, it might cost you quite a bit more. Most I/B use a top mounted starter. Bravos are on the bottom. You may need a new flywheel and starter.
If the I/B was mounted to an inline tranny (Velvet drive) it may have a manifold made for mounting at an angle. The carb will be higher in the back than front. Not sure if this is a big deal, but you might want to add the price of the intake. If it was mounted to a down angle I/B (BW 5000 or Twin Disc) this won't be a problem.
The I/B motor mounts are made to adjust right/left & up/down. They're actually quite sturdy but I'm not sure if they're made for the pounding of a sport boat. Add the price of offshore mounts.
You'll of course need a bravo bell housing and coupler if you dont have them already.
My $0.02.
Gary

They are hooking up to my existing bravo 1 i/o. gonna pull out my 454's. I am sending a picture of the motors. Looks like the exhaust is different than i expected.

oh here is the picture. thanks for the info

Outlawinil,
Exhaoust risers look like mine. They have a 6 inch spacer that can be removed if they exit too high for your current setup.

Bajaforce

Look on the valve covers and check the firing order listed on the spec decal on one cover of each engine. Chances are that they had Hurth transmissions (both engines will be std rot.) behind them but the firing order on the valve cover will confirm or disprove that. As a last resort, check the timing indicator at the front balancer to check which way the advance indicator is stamped. If they're both the same you've got standard rotation engines.
As far as starters and bell housings/couplers you'll need outdrive-style with the block mounted starters unless you're putting these in an older boat with TRS drives. Flywheels will probably be alright, but you'll need to switch the ring gear around to the front edge of the flywheel if you're using Bravos..

I also saw those on E-bay, Alamo is the seller. He used to sell a couple motors & parts on OSO, if I remember correctly. He seems to be pretty straight up kind of guy. Alamo is pretty knowledgeable about what is needed. Check out 1800-runsnew, crate 502 for about $5000-00, easy swop & they are new. Good luck
John

Have you looked at the Pulse drive instead of bravos
They use tranny’s like you have, so starter location, bell housing, couplers, exhausts, rotation should all be OK, the prices look pretty good to. Lots of info on the web www.pulsedrive.net