I just wanted to start this thread to try to help less experienced people learn more about what it takes to build a really nice engine... Think of an engine like a house, the block is the foundation. My approach is to take the engine to a machine shop, have them clean and mesure it out and let you know the amount on machine work needed to meet your goals. I let them disassemble the engine too because there are many clues they may find like worn bearings etc that may get missed if you just bring in a block And crank. Think of the tear down as a autopsy. Of course you will be tempted to tear it down yourself but I'm telling you most good machine shops would prefer to take it apart themselves and diagnose good and bad aspects of the engine. Taking shortcuts on the machine work is not a good investment. Even if you can't go with alum heads and super high HP right away you are still better off to invest in a properly blueprinted engine with all the clearances in spec. To start with make sure the engine is a good candidate for a rebuild and if it is then start by having the deck surface milled square to the crank centreline. Most blocks have some of the pistons sitting further down in the hole due to the block deck not being square. The mains of the block should be align honed or bored if needed after ARP studs are added in place of the old bolts. The studs give better clamping force but this may change the bearing clearances unless it's align honed or bored. If this is a mild build then stock bolts are fine. I only bore as much as needed, no more. I keep my cylinder walls as thick as possible. If the bores clean up at 30 thou overbore and you can get pistons then go for it. Not a huge performance gain by boring a little bit larger, and you loose valuable strength. If the cylinders measure out well then use stock sized pistons, it saves $ and leaves you more material for a future rebuild if needed. If you plan to use the TA alum heads (which are closed chamber) then shoot for a zero deck, which means the piston comes right up to the deck surface of the block at top dead center and your head gasket thickness of roughly 40 thou will be a good distance for quench. Think of quench as the "squish" zone between the piston and the head, this promotes more efficient air/fuel mixture burning. If you are planning to use iron heads the quench is far less important because the stock iron heads have an open chamber design. For the rods it's really best to get the new $600 replacement rods TA sells, it's great insurance for high RPM use. Plus how much money does it take to re-size stick rods and add ARP bolts? Likely not a big difference in cost. If this is a mild build the stock rods and bolts may work great just have them re-sized. Same goes for the pistons, spend a bit of money here to add longevity and performance. You can order custom pistons to give you any compression ratio you want and I suggest you run the pistons at zero deck so that with a 40 thou head gasket you have a 40 thou quench area which reduces detonation tendencies and increases combustion efficiency. Before ordering a custom piston ensure the block will clean up with your desired overbore, and ensure the shop measures the deck height of the squared off block decks so you can get your pistons ordered so they sit flush or zero deck. Ensure the rotating assembly is balanced. Internal balance for serious engines and external for mild builds. To pick your desired compression ratio look at the fuel octane options you have. Contrary to popular opinion you can still make some great power with a little lower compression ratio if all the details are well planned out. Being able to run an engine on mid grade octane instead of the premium grade would save you $ if you drive a lot. If the car is more of a race setup then high compression is a good option or forced induction is also very potent. Once you know your desired octane requirements you can match up the static or physical compression ratio with a camshaft that you pick and this will allow you to dial in your dynamic compression ratio which is just the way that the camshaft opens and closed the valves in the heads bleading off some compression or cylinder pressure. Power adders: Nitrous is very safe if used properly, contrary to many rumours nitrous is not flammable it simply let's the engine ingest more air which in turn let's us add more fuel to match. There is no danger to using moderate amounts of nitrous if done right, the only down sides are the costs to refil and the fact that it hits very abrubtly and can be hard on stuff. Turbos are pretty much free HP and they make boost only when the engine is under load... We can double the HP of a Buick 350 with turbos and keep the mild mannered low rpm drivability. No need for high compression or large cams. Properly sized there is no turbo lag . Superchargers are great but they require pulley changes to adjust the boost levels and they take a lot of power to turn. The advantage the supercharger thas is there is no lag in the boost. Sorry for the long post....
Hi Kevin I guess I would call a under 400 hp and under 6000 RPM Mild... Even though the 68-72 style rods are considered "weaker" than the 73-80 rods they still work great for the mild builds and the only time they have been breaking is with 450+ hp and over 6000 RPMs.
