budget 273 build

JJR said
Timing is Timing all it is used for is to get the spark to happen at the right time so you can build the highest combustion pressure possible when the Piston is near TDC. So if you had the same setup on two different engines and the only difference was compression ratio. The Higher Compression Engine would need less timing for a given fuel because pressure and heat would build to fast and the entire mixture would instantaneously all combust before the piston hit top dead center(detonate) an cause to great of an opposition to crank shaft rotation to be safe for the engine. So on both engines you can only build so much pressure just before TDC to prevent detonation. At and after TDC the Highest Pressure Possible is the goal. So wouldn't the higher compression make higher pressure. Fuel Efficiency would also increase to wouldn't it?

In practice, without getting into the complexities of combustion, there is a total timing setting that will produce the highest horsepower and lowest ET. It, typically, will only vary by a couple of degrees for an engine, this is why it is so important to find true TDC. It may be different for another engine. SB Mopar is around 35 degrees, an early Hemi is about 30 degrees, BB Mopar is around 38 degrees. If you build an engine with too much compression and have to back down to 25 degrees (Total advance, initial plus Centrifugal advance) to stop detonation on a SB Mopar, you will make less power and be less efficient than a 9.0 CR SB Mopar with 35 degrees of total advance. The problem is with the available pump gas, if you are driving on the street. 93 Octane pure gas if you are lucky, 91 with alcohol if not. A race car is much easier. You can get good gas, and you are only burning it 1/4 mile at a time. You have to look at the total package or you may end up with an expensive dog. Be realistic with what you want to do with your car, and talk to your cam company before you buy anything.