BLOCK
Finding a high quality short block is a huge factor in a quality engine build. Some things to check out when building a short block are as follows.

Bearings in crank / rods / floating pistons - Your bearings are the heart of your engine. I would suggest getting a tri-metal designed bearing. These bearings can handle higher loads and abuse as well as offer outstanding performance benefits. Buying a rod with floating (bronze brushed) pin end will also notice improved performance. The bronze, once lubricated creates a very low friction metal to metal contact. In essence once rotating up to speed the bearings don't even contact the pin, hence the name fully floating pistons.

Mains - The mains are where the crank is bolted into the block. Generally the more bolts that support the crank the better. This helps to eliminate crank walk which happens when the crank is spinning at high rpm or high load levels. What is crank walk? Crank walk causes massive engine damage and destroys bearings by actually distorting the block while the crank is literally moving forward or reverse in the block beyond where it should be. Most engines use 2 bolt mains and since there is only 2 fasteners per cap, crank walk is more easily achieved. 4 bolt mains are a bonus and help retain the crank position. I am lucky enough to be using a block with 6 bolt mains. Using a high quality fastener like ARP studs is a huge bonus, since they have a super high tensile strength they help support the crank even further from moving around in the block.

Block - About the only thing I can think of when it comes to actual block design would be to see if there is material in critical stress areas and there is ample webbing on the block. The webbing is used as reinforcement areas.

Decking the block - Decking the block helps eek any extra compression out of your engine by bringing the pistons closer to the cylinder head. This is done by removing material from the top of the block so the piston comes flush with the deck. Since I was doing combustion chamber work in which I would be losing some compression, I felt it would be best to live with the piston being slightly down in the block. Since SC and turbo cars generally run a low compression ratio it's an unnecessary investment also.

Ring the block / Headgaskets - Ringing the block has been a common practice among many high end engine enthusiasts for a long time. Tired of blowing head gaskets? O-Ring the heads and block. This is done by machining a crevice into the head and block and literally placing a metal O-Ring in this crevice in place of where the gasket would normally sit. Gaskets are flush and since the O-Ring penetrates the heads and block it's pretty much a permanent seal. This is generally a good idea for super high output engines. In the case of a daily driver, it's not as necessary. In high boost applications it is absolutely necessary in my eyes unless you are using an ultra high end head gasket such as Cometic MLS gaskets. These are steel reinforced gaskets as opposed to what I call as "the other material head gaskets" There is Steel and Copper and then there are "the others" I opted on using an MLS head gasket and forgo the O-ringing. They say the MLS head gasket is good for ~20 psi on a boosted application which would be overkill for the street so O-ringing wasn't really necessary, especially on a naturally aspirated engine. Copper head gaskets are also good in my opinion.

Balancing - Balancing the rotating assembly is huge in terms of importance in a high power, high revving engine. The closer the assembly is to perfect rotating weight the easier time the engine has rotating the assembly (pistons, crank, rods) Generally +- 5 grams seems to be the industry standard. I have opted to balance to within +-1.5 grams. This will bring greater high rpm capability to the engine and create a more balanced load in the block. The less the stress due to shaking of in balanced rotating assembly the more the power and less the stress on the block etc.

Piston Choice - A balance between weight and strength should be found in the piston. A high quality forged piece is the only way to go in my opinion. Forged Pistons handle higher stress and can be found in lightweight configurations. The lighter the piston the faster the engine can rev. With most turbo and supercharged cars I would suggest going with a heavier piston that can handle some massive heat and abuse.

Compression Ratio - This is the compression of the combustion chamber when the piston reaches top dead center. The higher the compression the better the power output of the engine. I could get into a lengthy explanation but lets just say its the engines natural tendency to pull air into the combustion chamber and expel exhaust. The higher the compression the better it can perform these tasks. A 10:1 compression ratio is a good starting point for a naturally aspirated engine (my level). An 8:1 compression ratio is a good starting point for a high boosted vehicle. A street turbo and supercharged engine should have a lower compression to reduce the chance of engine damage due to pressure in the cylinders and the potential problems it brings.

Rod Choice - Just like the pistons, a lightweight forged rod is a great choice but a billet rod is the best. Knocking in at an ultra light weight and extremely high durability you have to pay to play with these boys (try over $2000 for a set) but is well worth the investment. You could also go with a quality, strong forged piece for about half the cost that can handle ultra high hp levels but are going to pay in weight. Having a lightweight rotating assembly means at high rpm there is less stress placed in critical areas of the block and rotating assembly, including the mains, when rotating at high rpm's/loads. The less the stresses in the block and rotating assembly, the less the distortions in the block and the greater the power output. Blocks do distort under high load levels/rpm. Again, with the potential of turbo and supercharging I would suggest using a heavier/stronger forged piece with ARP fasteners if you decide to use a forged rod. Having a bronze bushed pin end is also a bonus. Many aftermarket pieces fail to use a bronze bushed type pin end.

Rod Ratio or Rod Angularity
The ratio between the stroke length of a motor (A) and the connecting rod length (B) greatly affects the way it works, and how long it lasts. The rod’s length is measured from the center of the piston-pin opening to the center of the big-end bore, not overall. There is a small range of ratios for most conventional piston engines: the rod is roughly between 1.4 and 2.2 times the stroke length. It’s not possible for the rod to be the same length as the stroke, and rods much longer than twice the stroke make the motor very tall, and are not practical for most purposes except racing. Longer rod engines create less friction between the piston and the cylinder wall, and a greater percentage of the combustion process is delivered to the crankshaft in the form of work. Additionally, a longer rod allows the piston to "dwell" more at TDC, allowing a good flame-front to form in the combustion chamber. If however the rod is too long, the wrist-pin will encroach on the ring package, and could compromise oil control.

Also, the ratio between bore diameter and stroke length will determine the engine characteristics. A shorter stroke engine with a large diameter piston will create an engine with high revving capabilities and low torque and power down low in general. A longer stroke engine than bore size creates more bottom end torque and power in general but is seriously limited in top end revving capabilities. The engine I decided to build up is square in nature so it should have a balanced powerband with 7000-8000 rpm max capability.

Crank Choice - Hmmm Forged crank or go home. It sucks in that a forged piece is about double the weight as a cast piece but durability of the piece is a huge added bonus. Some options are to Nitride the crank or Cryo treat the crank so that they do not get scored and can handle even more abuse but I opted to deal with the standard forged piece since it easily handles 1000hp without breaking a sweat. The Cryo process is also nice since it helps prevent scoring of the journals etc. Honda engines are lucky enough to come stock with Forged pieces that are Nitrided from the factory. You can also do something called knife edging. The crank counter weights are cut to a knife like edge which helps reduce windage of the crank. What is windage? Think about it this way. Drive 100km/h and stick your hand out the window. The drag is highly noticeable, now think about doing that through a heavier medium such as oil. Your crank is always sloshing around in the oil. This creates a huge amount of drag on the crank in which you loose insane amounts of horsepower due to windage. The knife edge of the crank helps create a cutting device instead of a blunt end through the air and oil in the oil pan/block. This has it's benefits and some drawbacks. The benefits are obvious, say 20hp or more on certain applications, the potential negatives are that your rotating assembly is now way to light. So what negative could that have? An engine idles because of rotating inertia. Off the line power is also created due to rotating inertia in your rotating assembly and flywheel. If you don't have enough your idle has to be raised. Raised idle for a street car and no off the line power...ugly!

I forgot about the knife edging since the rotating assembly/flywheel was already lightweight and dealt with the oil windage problem in another way... keep reading.

Oil Pan - Stock Oil pans, to put it bluntly usually suck. Oil control is limited and as stated above keep the oil around the crank which causes windage and HP loss. When you make a hard corner, guess what, the oil goes sloshing around on your crank away from your oil pickup, lowering oil pressure, and failing to lubricate your engine parts as well as robbing you of horsepower. The fixes are here people. 3 things.

1) Windage Tray - the windage tray is a device that usually scrapes excess oil from your crank and keeps oil from being able to jump back up on the crank causing HP loss. It usually bolts onto the bottom of the block or onto the mains between the oil pan and block.

2) Buy an oil pan with Kickouts - kickouts on an oil pan do 2 things, increase the volume of the bottom end which in turn creates more power and during hard corners traps the oil within the kickout so that it doesn't splash back up on the crank.

3) Buy a dry sump system - My setup will consist of a dry sump system. This means that any oil in the pan area will be sucked out and the engine is essentially dry at all times except for the oiling passages. This keeps the oil from causing windage on the crank. A dry sump system can also be setup to suck the air out of a crank as well which in turn even removes the air resistance on the rotating assembly.

Ring Gap - Typically you want to hand file fit piston rings. It's important to have the ring gap larger on the top ring than the bottom because it expands more due to the extra heat in the combustion chamber. A lot of people are sold on those total seal piston rings, which are fine, but during my research have found that some vacuum in the piston ring area is a good thing which controls oil in the ring area better than having the ring area totally sealed off. The vacuum in the lower ring land area expands the rings and seals the ring better to the cylinder wall. This in turn allows the rings to scrap excess oil from the cylinder more effectively. Oil then cannot reach the cylinder which has a tendency to cause detonation even in the slightest amount within the combustion chamber. Without that vacuum at times oil dwells in the ring land area potentially making it to the combustion chamber.

Material Type - Obviously a cast iron block strength wise is best, but the 80-100 potential pounds you save from an aluminum block is also critical to racing. Having 4 or 6 bolt mains I would tend to lead towards going with a quality aluminum block. 2 bolt mains, don't even think about aluminum... my 0.02 cents anyway, everybody has their preference. An IRON 4 bolt main block is pretty much indestructible.