the answer is 357 ci (and some change).
4.000" the engine bore size
4.00"
4.030"
stock bore is 4.32 inches, so 30 over would be 4.35 inches
Over Size
4.165"
A typical bore size for a Chevy 350 engine is 4.000 inches. A bore measurement of "sixty over" indicates that the bore has been increased by 0.060 inches, resulting in a final bore size of 4.060 inches. This modification is common in engine rebuilds to increase displacement and improve performance.
3.671 plus 0.030 is 3.701, about 310 cid. Maximum bore is about 3.8583 (98mm).
421 c.I.d.
the biggest difference is obviously the stroke and bore of the engine and the size of the engine
283 bored .060 over should b abour 292 cubics A standard bore 283 was 3.875", so 60 over would be 3.935.