My first engine was out of a 1962 Austin Healy Sprite. 1098 cc before cylinder cleanup. I didn't have much done at the machine shop. Cylinders bored, block deck and head mating surfaces flycut. Pistons knurled. (Worked great) I guess I had it tanked.
I made three mistakes:
1. Didn't mark the main caps so I installed all three backwards. Engine didn't crank. Broke the rear end trying to tow start.
2. Didn't replace the oil pressure relief valve piston. It was running 85 psi and blew off about four filters before I caught that one.
3. Painted the block white.
The first one is always a learning experience. It's beyond price. The second one will cost a lot less and take a lot less time . . . but you have to do the first one to get the benefits.