Use a good assembly lube when putting your engine together.
Johnson says Internet know-it-alls and overanxious zealots who focus on the most minute details are often more difficult to deal with than customers who care too little. Any engine builder worth his salt knows which parts and processes work and which do not. Asking for clearances to be machined to the hundred-thousandths of an inch or informing them that Brand X's zinc/krypton bearings are a nonnegotiable requirement for the build because you read about them on some message board won't help you in the long run. Trusting the shop to put together an engine package for you will often result in an engine that makes more power and lasts longer than one in which you micromanage the build. Unless you're an expert machinist and mechanical engineer and know all the nuances of machining and matching parts, let the builder do his job.
Early in the conversation with your builder, the following question will be put to you: Do you want to build a stroker? Johnson says that is often a difficult question for guys on a tight budget to answer. Do you add extra cubes to make more torque, or do you spend your money on the cylinder head to improve airflow and make more horsepower at higher rpm? The answer largely depends on your car: How heavy is it? What is the rear axle ratio? Do you have an overdrive transmission? What are your gear ratios? Discuss all these variables with your builder. His experience will enable him to recommend a package that will best meet your needs.
Here's a standard journal crank. Below is a crank with filleted journals.
Block
Though we'd all love to begin our build with an aftermarket block, the reality is most budgets don't permit it. And honestly, most of us aren't making power levels high enough to warrant the purchase of an aftermarket block. Johnson says the rule of thumb of 1.5 hp per cubic inch is about the limit of most factory engine blocks. So if you have a stock 350 Chevy and are planning to make more than 525 hp, you should be seriously considering a phone call to Dart, World Products, GM Performance Parts, Ford Racing, or Mopar Performance. Why? "Aftermarket blocks have improved oiling, thicker decks, thicker cylinders, and are made with more alloy. They are a stronger block," Johnson says.
Likewise, if the amount of machining you're considering is going to cost more than $1,500, you should also consider an aftermarket block. At that price, the cost of machining is approaching the cost of a new block in some cases, and you'll have a much better engine in the end if you spend a little extra for the aftermarket block. But be careful-aftermarket blocks may require machining of their own and that adds to the total cost.
This is a performance crank with filleted journals.
Still, for most street cars, the stock block will handle a lot of abuse. But there are several things you can do to improve its strength and performance. One of the most popular upgrades is to drill and tap the block to accept four-bolt main bearing caps. Often mistaken as inherently stronger than two-bolt mains, the real purpose of four-bolt caps is to prevent cap dancing or cap walk that occurs on the down load-the load placed on the cap as its adjacent crank throws are rotating down. Of the two types of four-bolt caps, splayed caps are better at controlling cap movement than straight caps. "They spread the clamping load over a larger area and are threaded into a stronger part of the block-the webbing," Johnson explains.
Steel caps resist flex better than stock cast-iron caps but may be a luxury item that could be eliminated for the sake of keeping the build within your budget. If you reuse your stock caps, be sure to keep them in order-this is extremely important. Number them and make some kind of mark indicating which side faces forward. No two blocks are the same; there can be differences in the size, shape, and thickness of components in a single casting. Because the main bearing caps are part of the engine block casting, the caps will vary slightly in shape from one to another, so they need to stay with the journal to which they were originally machined.
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