OK, sounds like someone has had this apart, so be careful here….Why would the compression be low if this had been rebuilt? Were the cylinders scored/pistons scuffed? You will want to measure the piston skirts and cylinder bores carefully before proceeding..Someone may have “honed” the cylinders excessively to get rid of scores instead of boring oversize. When you speak of “dowels”, do you mean the locating pins for the crank bearings in the block journals? This is another thing to worry about, perhaps the crank bearings were never properly aligned during the last rebuild. Misaligning the bearings/dowels/pins will damage the bearings, crank, block, and could have distorted the crankcase halves so they don’t fit together properly anymore.
I don’t mean to sound discouraging, I just don’t want you to invest money and time into this project only to have it not work out due to “built in issues” left behind by previous work.
Let me know if you want to email pictures to me if you can’t make them fit here….Don
