i got my 307 olds engine out of the machine shop which set me back almost 1500! But i'm very happy with the results. The man helping me said that they bored it either .030 or .040 over. What I want to know is what is the CID now if its .030 over and .040 over and maybe what is the liters now? It was a 5 liter but i dont know what it is now D:. Anyone have any idea?

 

310 or 312 cubic inches.

 

Let's go through this.

Your nominal displacement is 307ci.

That comes from calculating the theoretical volume of 8 cylinders, each with a bore of 3.800" and a stroke of 3.385"

Area=∏r2, or Pi x radius x radius

3.800" is the diameter, so 1/2 that is the radius: 3.800" / 2 = 1.900"

So, A = ∏ x 1.9" x 1.9" = 11.34 sq in

To get the volume of a cylinder, we multiply the area of its circle by its length.
So, V = 11.34 sq in x 3.385" = 38.3859ci per cylinder.

Since there are 8 cylinders, we multiply 38.39ci x 8 = 307.12ci
which is your nominal displacement.

Your motor was bored 0.030" over,
So, Bore = 3.800" + 0.030" = 3.830"

∏ x 1.915" x 1.915" = 11.52 sq in x 3.385" = 38.9952ci x 8 =311.99ci

Your motor is now a 312.

(that's 5.113 litres)

- Eric

 

The top of the piston should be stamped '+.030' or '+.040 - did they assemble it for you?
Complete or shortblock?
Just remember to 'prime' the motor b4 firing!