The Baltimore Orioles had the highest run differential by a team in 1966, with a differential of 154 runs.

	TEAM	DIFF	SEASON	G	W%	W	L	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Orioles	154	1966	160	.606	97	63	5,529	755	1,426	243	35	175	703	514	39	926	55	43	6,199	2,264	453	82	35	59	119	.258	.324	.409	.733
2	Pirates	118	1966	162	.568	92	70	5,676	759	1,586	238	66	158	715	405	35	1,011	64	60	6,229	2,430	462	73	40	75	111	.279	.329	.428	.757
3	Dodgers	116	1966	162	.586	95	67	5,471	606	1,399	201	27	108	565	430	49	830	94	64	6,066	1,978	336	84	32	54	117	.256	.314	.362	.675
4	Braves	99	1966	163	.525	85	77	5,617	782	1,476	220	32	207	734	512	40	913	59	47	6,286	2,381	459	72	45	75	106	.263	.326	.424	.750
5	Twins	82	1966	162	.549	89	73	5,390	663	1,341	219	33	144	611	513	39	844	67	42	6,035	2,058	396	49	44	69	138	.249	.316	.382	.698
6	White Sox	57	1966	163	.512	83	79	5,348	574	1,235	193	40	87	524	476	44	872	153	78	6,021	1,769	320	109	44	50	94	.231	.297	.331	.628
7	Phillies	56	1966	162	.537	87	75	5,607	696	1,448	224	49	117	628	510	29	969	56	42	6,256	2,121	390	78	32	64	113	.258	.322	.378	.700
8	Giants	49	1966	161	.578	93	68	5,539	675	1,373	195	31	181	627	414	32	860	29	30	6,083	2,173	407	70	28	65	142	.248	.303	.392	.695
9	Tigers	21	1966	162	.543	88	74	5,507	719	1,383	224	45	179	682	551	33	987	41	34	6,195	2,234	448	67	37	45	128	.251	.321	.406	.727
10	Yankees	-1	1966	160	.440	70	89	5,330	611	1,254	182	36	162	569	485	21	817	49	29	5,936	1,994	380	58	42	41	111	.235	.299	.374	.674
11	Cardinals	-6	1966	162	.512	83	79	5,480	571	1,377	196	61	108	533	345	35	977	144	61	5,963	2,019	365	59	44	51	114	.251	.298	.368	.666
12	Reds	-10	1966	160	.475	76	84	5,521	692	1,434	232	33	149	651	394	20	877	70	50	6,043	2,179	414	69	39	56	117	.260	.309	.395	.704
13	Indians	-12	1966	162	.500	81	81	5,474	574	1,300	156	25	155	536	450	27	914	53	41	6,040	1,971	336	56	33	55	113	.237	.297	.360	.657
14	Angels	-39	1966	162	.494	80	82	5,360	604	1,244	179	54	122	562	525	38	1,062	80	54	6,038	1,897	355	69	46	52	104	.232	.303	.354	.657
15	Red Sox	-76	1966	162	.444	72	90	5,498	655	1,318	228	44	145	617	542	32	1,020	35	24	6,175	2,069	417	65	38	54	131	.240	.310	.376	.686
16	Astros	-83	1966	163	.444	72	90	5,511	612	1,405	203	35	112	570	491	34	885	90	47	6,170	2,014	350	97	37	61	128	.255	.318	.365	.683
17	Athletics	-84	1966	160	.463	74	86	5,328	564	1,259	212	56	70	509	421	26	982	132	50	5,873	1,793	338	71	27	34	100	.236	.294	.337	.631
18	Senators	-102	1966	159	.447	71	88	5,318	557	1,245	185	40	126	525	450	20	1,069	53	37	5,905	1,888	351	84	33	31	130	.234	.295	.355	.650
19	Cubs	-165	1966	162	.364	59	103	5,592	644	1,418	203	43	140	603	457	47	998	76	47	6,213	2,127	386	80	37	53	112	.254	.313	.380	.694
20	Mets	-174	1966	161	.410	66	95	5,371	587	1,286	187	35	98	534	446	42	992	55	46	5,951	1,837	320	63	29	44	127	.239	.301	.342	.643