can you use a older bravo 1 upper unit with a newer lower bravo 1 unit?

Ken,
You can if the upper has the oil passage that the lower has. In the very early bravos, they didn't have an island in the water tunnel with a hole drilled in it that transfers oil from lower to the upper. If the upper has the hole for the oil, it will mate with the lower ( all newer ones have it) and should be fine. Just match the two up and you will be good.

Hope that helps.
Dick

no thats not the answer I was looking for. Someone told me that you can plug up the hole in the lower, but I looking for someone who may have done such a thing to confirm it will work. Thanks anyway for your time.
My upper is the older with out the hole and my lower is a new casing with the oil hole. My Question here is will it do any damage to have that hole plugged of to the lower?

no it will not hurt to plug the hole but, it would be a good idea to use a drive shower to keep the drive cool since you wont have as much oil circulation.

thanks past due anyone else tried such a thing? and any input on plugging the hole?

Yes, no issues

Small soft plug or welch plug from NAPA

thanks Greens Marine

thread the hole and use a pipe plug thats what imco says to do when using their stuff that wont match up.

On the older upper cases without the hole there is another hole in the vertical shaft cavity.. I have drilled that hole on the opposite type of swap.
Sorry I didnt understand your question.. but looks like others have answered it.. Happy boating.
Dick