is there a difference from the street motor

Standard rotation engines are still 1-8-4-3-6-5-7-2 and reverse rotation engines are 1-2-7-5-6-3-4-8

http://www.basicpower.com/firingorder.htm

All I/O engines are standard rotation. The rest you need to confirm, but yes Blazin72 speaks wisely. Same firing order.

Just curious... are you planning on putting a marine block on the street? If so, make sure it never had salt water circulated through it. Salt gets in the pores and never really comes out ever. Salt and anti-freeze don't like each other.

Actually it was common on twin engine boats in the past to change the rotation on one engine.

Not in I/O appications. The reversing of rotation takes place in the outdrive. On INBOARDS like Vee drives or direct drives, yes, but not I/Os. Its kinda like 4x4 axles; if you have an axle with a pinion offset to the right, you can't flip it for an application that the pinion is on the left. The gears don't mesh properly when you drive them backwards. You have to have a completely different axle.

The same is true of outdrives. You can't just turn the engine the other way or the outdrive will be destroyed. You have to use a reverse-rotation outdrive and then drive the engine in the standard direction.

In current outdrives you are currect, but I can show you my old combinations with TRS drives, and with Speed Masters IIIA that used one standard rotation engine, and one counter rotating engine.

Heck I know of a race team out there right now using Dry Sump #6 drives with one engine being a counter rotator...

thanx everyone for the info....it turns out it was a reverse rotation motor in a single motor application???? who would of thunk?