Learning as I go

Here's my changes since last year everything else remains the same.

shaved .050 from the head to increase compression to approx. 9 to 1.
swapped a LOM dist. for a DSII dist.
stock cam to 264/264/110 clay smith
302 V8 springs on the valves was 6 cylinder springs

Out driving on the expressway today and 70 mph was approx. 2100rpm on tach. Last year it took 2250 to yield the 70 mph. Will the compression increase lead to the drop in needed rpm to produce 70 mph? I'm just trying to learn cause and effect.

actually the power increase overall is what led to the drop in engine rpm to reach 70. understand that if you calculate what rpm you should be running at a certain speed, it will not match with reality because you have friction losses, as well as aerodynamic losses. when you increase available power, you overcome these losses somewhat, and the engine doesnt have to work quite as hard as before, thus it doesnt run at as high an rpm, assuming that everything else remains the same, gearing, tire size, etc.

Engine rpm is directly due to gearing and tire size and nothing else. Converter slippage may be a variable but it is not likely here and unless you changed drivetrain components your engine rpm at a given speed has not changed, it is physically impossible. Could be an inconsistant tach reading as I have seen tachs "wander" quite a bit especially if it is a cheapie or an old model.

Frictional and aerodynamic losses will reduce engine EFFICIENCY, but these things will never alter the engine rpm at a given speed.

Hey Denny, just noticed this antique thread and you stated you had .050 cut from the head on that old build. Didn't you tell me you had it cut .050 for this build? It wasn't cut twice was it? With 100 thou removed you would have a pretty weak deck surface, I hope I am remembering wrong.

The head was only cut once the .050. Maybe your blood/acetone level was elevated at some point??? (hahaha)

Mr Comet":x7azx8ag said:

The head was only cut once the .050. Maybe your blood/acetone level was elevated at some point??? (hahaha)

Click to expand...

first fox have you been nipping at the acetone again? :mrgreen: :mrgreen:

Hahaha... Yeah maybe so guys. Even though the ingestion of toxic chemicals may affect my memory, it also lessens the pains of having this as a hobby as opposed to collecting stamps or weaving baskets or something. 8)