All the above is good advice. I've built a few but it was many years ago. I also shopped for the best parts at the best prices I could find and did my own work except for the machine work. A good machine shop will let you know what you need or don't need.
The best one I ever built was with a performance cam, over sized valves, port work, header and I think I used 2 1/4" exhaust. Just a turbo style muffler since I don't like loud anymore. I deleted the EGR but I still used a cat. The cam and O/S valves were from Engnbldr.com that is now out of business. He sold the business to the shop that was grinding his cams and they are still in business.
Performance Camshafts | United States | RedLineEngineBuilders.com - https://www.redlineenginebuilders.com/
I used a 270 cam. It was the largest cam recommended for the stock EFI and it was my favorite of all I have used. It made a big improvement for street and highway driving for my daily commute. I had MANY people telling me it would kill low end performance. It was SLIGHT and the mid range was awesome. I had low range gears in the T-case for off road and I had ZERO regret running that cam. I had 31" tires and 4.56 gears at the time I built it and it still was awesome when I went to 35" tires and 5.29 gears. Just my personal experience.
Since head gaskets failures are common failures, the deck surface has to be good as does the head surface. Don't jus replace the gasket. And use OEM head gasket as recommended above. I also agree with the steel backed timing guides.
I blended the bowls after the larger valves and gasket matched the ports. Nothing crazy with the port work. OEM head is best if it can be reused.
Make sure the rocker assemblies come apart for cleaning and inspection. OEM rocker pads can be resurfaced if needed. Adjusting bolts often are beat on the ends and make it difficult to adjust the valves if bad enough. Might need new ones.
Tank/soak the intake because the plenum will be caked with carbon and gunk from the EGR and PCV.
Have your radiator cleaned or replaced if needed before you put your engine back in service. Many people have over heated the engine on the first run because air trapped in the cooling system. Tons of info on burping the system out there. Have your heater on too to vent the air.
I fill the system slowly with the T-stat out and the housing off just to be sure. When the coolant reaches that level, I'll put the T-stat in, housing on and the upper hose, then top off the radiator. The reason I do it that way is because ONE time I had trapped air even after burping it and thinking I was good to go.
However you decide to go, good luck with your rebuild.
