350 Crank:
The 350 crank has a stroke of 3.48 inches. To calculate the CI of a 305 block with a 350 crank, you need to know the bore size of your 305 block. The standard bore size of a 305 is 3.736 inches. Using the formula for engine displacement:
CI = (Bore Diameter)^2 x Stroke x Number of Cylinders / 28.3
For a 305 block with a 3.736-inch bore and a 350 crank with a 3.48-inch stroke, the CI would be:
CI = (3.736 x 3.736) x 3.48 x 8 / 28.3
= 5.1408
Therefore, the resulting engine would have a displacement of approximately 355 CI (355.1408) with a 350 crank in a 305 block.
400 Crank:
The 400 crank has a stroke of 3.75 inches. Using the same formula as above, we can calculate the CI for a 305 block with a 400 crank and a 3.736-inch bore:
CI = (3.736 x 3.736) x 3.75 x 8 / 28.3
= 5.5644
Therefore, the resulting engine would have a displacement of approximately 400 CI (399.5644) with a 400 crank in a 305 block.
It's essential to note that these calculations assume a standard bore size of 3.736 inches for the 305 block. If your 305 block has a different bore size, the CI will vary accordingly. Additionally, some modifications may be required to accommodate the longer stroke of the 350 or 400 crank, such as clearancing the block and/or the oil pan. It's recommended to consult with an experienced engine builder or machinist to ensure proper fitment and performance.
