This is also the origianal engine in the boat.

I am trying to find out how both engines are balanced.

The 1988 block is a roller set up w/ neutral balancer and external flywheel.
Bob

lim,
Some of the early "roller" blocks had lifter bores that were not the same size from top to bottom. They were used in truck engines that did not have roller cams. If you try to go with a hydraulic roller on these blocks you will have oil pressure problems. You have to look at the lifter bore in the block. If it is the same size all the way from top to bottom, you are ok. If there is a step at the top, making the top 1/2" or so a larger diameter hole, you can only use non-roller lifters. The roller lifters have thier oil hole higher in the body than the non-roller lifters do. When they come up on the top of the cam lobe, the oil hole is exposed in the stepped area of the bore and you lose oil pressure. I found this out the hard way on an engine I built for my own Blazer I have only seen a few of these blocks over the years so I don't know how common they are.

How can i tell what year it is by the number on it?If I remeber right isn't the SBC casting number on the back by the bellhousing area? What number converts to year?
The boat is an 88 but that does not mean the engine was cast in 88.