As Bill mentioned 360s always seem to magically gain some stroke and become 390s when they are being sold so if you determine that the engine is in fact an FE and the vin says 360 but the guy says it's a 390 the only way you can verify is measure the stroke. A 360 is 3.50" a 390 is 3.784" (just a hair over 3-3/4 if just using a tape measure) externally you can't tell the difference otherwise.
since it's a 2wd a 390 is possible so verify with the vin.