leaded or unleaded fuel
Here is an example of why you need to cc the piston(down fill) to be accurate on your compression.
My 340 piston set .017" above the deck.
as you can see below that creates a 3.57 cc dome above the deck.
now drop it down the hole .500" and cc the volume.
4.04 bore .500 stroke=105.03 cc. My down fill volume was 112.04 aka like a dish piston would do. but it has a pop up??????
The reason why is that the Valve reliefs were larger then the pop up of the piston.
In other words i had a pop up piston. but the valve reliefs made it act like a dish piston.
aka a 10.5 piston figured out to be only 9.4:1 compression.
I may have fudged a little on my math but you get the point.
Here is an example of why you need to cc the piston(down fill) to be accurate on your compression.
My 340 piston set .017" above the deck.
as you can see below that creates a 3.57 cc dome above the deck.
now drop it down the hole .500" and cc the volume.
4.04 bore .500 stroke=105.03 cc. My down fill volume was 112.04 aka like a dish piston would do. but it has a pop up??????
The reason why is that the Valve reliefs were larger then the pop up of the piston.
In other words i had a pop up piston. but the valve reliefs made it act like a dish piston.
aka a 10.5 piston figured out to be only 9.4:1 compression.
I may have fudged a little on my math but you get the point.
