When I was about 6 or 7 my Dad pitched an old self propelled rotary mower, and kept the engine off of it. He showed me how to take it apart and put it back together. Then he had me do it. He gave it to me. I must have taken that engine apart and put it back together a million times. I spent half my child hood dragging lawn mowers out of dumps and getting them to run again.
By age 15 I had helped a friend build a 396/402 in his 1970 SS Chevelle. By 18 I had built a 327, & 350 Chevy, and 400 Chyrsler. At this point, in my life it was all redneck try it and see what happens, coupled with talking to other red neck gear heads.
Since then I have read a lot of books, learned a whole lot of things, I didn't know and likely got lucky on back then. I helped my sons build a few engines, as an adult.
That said, with your skills, I see know reason you could not build a small block, if you read some good books on the engine you are going to build. The critical factor is to understand the special little things that the particular engine you are building may have that is easy to miss. If you do your home work, you could build an FE, but they are full of things you have to know. It may be the most difficult engine to do. The good news is the SB Ford is a fairly easy design to work with.
There are still little things that you just have to know, like making sure the
oil pick up is not too close to the bottom of the
oil pan. Also there are a lot of things that require machine work, so work with a good shop to get all that done right.
Next you want to clean clean clean and clean again everything. Keep
oil on parts so they do not rust and keep them covered so dust doesn't get on the oil.
Now assemble - don't bother to torque - check fit and disassemble as many times as necessary to be certain you know what you are doing and have everything perfect.
This is a generalization that is missing a whole bunch of specific things. Like putting rings in the finished bore and squaring it with a piston. Then checking the ring gap to make sure it is in spec. There really is a lot of things that should be done, that if you buy all the right parts and get lucky they will fit, but if you do not check you just might have to start all over again.
PS
I learned the hard way on the BB Chrysler that if you bolt the rocker arm shaft on upside down, no oil is pumped to the top of the engine. Lot's of little things that you could easily over-look.