like Pontiac V8's(except 265 and 301), the external sizes are the same. For a "small" block displacement, it has a large bore,4.08" and medium stroke,3.44. Intakes stock are 2.025 and exhaust 1.68. BBM valves fit, 2.08 and 1.74. Oiling system is what it is. Could stroke it with a 401 crank, if you can find one inexpensive. Heads are good flowing. They are externally balanced.