big block

Mark, You may need to use some penetrating oil on the mounts. They can be stubborn at times. Then a pry bar and some wood blocking between the engine and the mounts and it should move. In extreme cases, the mounts may need to be removed and loosened up on the work bench. This is true with any engine and not limited to a big block.

I,m glad you found us at CCfan. You'll find lots of knowledge and plenty of helpful people here. Fill us in on the boat and better yet, post some pictures.

if you do end up removing the mounts which you probably will end up doing, i will put them in a blast cabinet which some guy's may not have access too,
another great way to clean them is a bench mounted wire wheel, once cleaned i will paint appropiate parts and never sieze the rest, once done you should be able to adjust the side to side easily with small pry bar. It sounds like the alignment has'nt been attempted in some time.
good to hear your doing the alignment, where did you hear about alignment?

thanks for your input guy, I noticed on the front mounts a big difference in space from right to left, But the couplers are real close. I read the front mounts should be 1 3/4 on each side is this so!!

Mark, Don't worry about the engine not being centered exactly in the middle of the boat. The hulls aren't the most precise things around. The important thing is to understand that the alignment starts with the strut and then goes forward. If the shaft is is centered in the strut cutlass bearing and roughly centered in the hole in the bottom/shaft log, then align the engine to the shaft.

The coupling to the shaft is a press fit so with all that play you mentioned, it has been run for some time without a alignment. The worst problem mis alignment can cause is blowing the output bearing (and then the seal) on the trans. How is it? As long as you are going with a new shaft and coupling half, now is the time to put a new dampener plate in on the trans. How many hours are on the boat?

a good indication of mis-alignment over the years would be a loose prop shaft coupling, it tends to take the abuse of mis-alignment and tries to act as a u-joint and works on the shaft causing wear, if you pull it off easily and has rust in that area then your coupling is worn.

eric lavine wrote: if you pull it off easily and has rust in that area then your coupling is worn.

What Eric is describing with the rust is quite common in mis aligned mechanical power transmission. I've had mechanics come to me with a rusty shaft, sheave, sprocket, coupling, etc. They will tell me that there is no water in the area and are confused about the rust. "Fretting" as it is called will actually be more without any water! Here's a link to a good explanation if anyone is interested.

fretting

Mark, Make sure you mike the diameter of the shaft if you are thinking about using it again. The wear from fretting is worse on softer materials (the stainless shaft).

If that info on fretting doesn't make you a believer in maintaining alignment, I don't know what will. 82% decrease in fatique life!