most wins in modern times in a season by a pitcher without a loss

Walter Johnson had the most wins in wins when playing >0 seasons, with 412 wins.

Interpreted as:

most regular-season wins in modern times in a season by a pitcher without a loss

	NAME	W	L	SEAS	W%	L%	G	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Walter Johnson W. Johnson	412	0	20	1.000	.000	518	412	1.24	2,383	339	108	34	3825.2	2,769		812	49	815	116	100		14,804	83	5.61	1.92	2.92	0.12	16.1	5.5	0.94	.238	1.91	6.51
2	Grover Alexander G. Alexander	373	0	20	1.000	.000	488	407	1.74	1,615	342	90	33	3710.1	3,098		964	101	635	34	70		14,553	22	3.92	1.54	2.54	0.24	11.1	4.4	1.01	.246	2.34	7.51
3	Warren Spahn W. Spahn	363	0	21	1.000	.000	505	438	2.24	1,837	324	63	28	3738.2	3,082	929	1,047	249	931	24	52	25	14,892	48	4.42	2.24	1.97	0.60	12.3	6.3	1.07	.239	2.52	7.42
4	Greg Maddux G. Maddux	355	0	23	1.000	.000	517	514	2.21	2,454	92	35	0	3635.2	3,027	892	998	194	630	82	2	78	14,293	48	6.07	1.56	3.90	0.48	17.2	4.4	1.01	.259	2.47	7.49
5	Roger Clemens R. Clemens	354	0	24	1.000	.000	525	523	2.31	3,641	92	46	0	3767.2	2,888	966	1,052	208	1,084	108	0	25	15,042	106	8.70	2.59	3.36	0.50	24.2	7.2	1.05	.268	2.51	6.90
6	Steve Carlton S. Carlton	329	0	24	1.000	.000	497	469	2.37	2,968	216	55	2	3700.1	2,972	974	1,098	235	1,155	36	12	66	14,872	126	7.22	2.81	2.57	0.57	20.0	7.8	1.12	.261	2.67	7.23
7	Nolan Ryan N. Ryan	324	0	27	1.000	.000	515	482	2.01	3,886	163	61	3	3610.2	2,233	807	923	147	1,670	93	12	29	14,520	142	9.69	4.16	2.33	0.37	26.8	11.5	1.08	.239	2.30	5.57
8	Don Sutton D. Sutton	324	0	23	1.000	.000	518	503	2.28	2,549	151	58	5	3767.0	2,920	954	1,047	275	873	45	10	46	14,891	69	6.09	2.09	2.92	0.66	17.1	5.9	1.01	.237	2.50	6.98
9	Phil Niekro P. Niekro	318	0	24	1.000	.000	590	454	2.43	2,288	182	45	29	3706.0	3,068	999	1,165	260	1,172	85	76	32	15,076	135	5.56	2.85	1.95	0.63	15.2	7.8	1.14	.249	2.83	7.45
10	Gaylord Perry G. Perry	314	0	22	1.000	.000	512	438	2.12	2,418	227	53	10	3671.2	2,976	866	1,014	195	856	62	24	64	14,555	93	5.93	2.10	2.82	0.48	16.6	5.9	1.04	.252	2.49	7.29
11	Tom Seaver T. Seaver	311	0	20	1.000	.000	451	444	2.10	2,687	186	61	1	3489.1	2,585	814	882	222	925	41	4	58	13,719	74	6.93	2.39	2.90	0.57	19.6	6.7	1.01	.240	2.27	6.67
12	Tom Glavine T. Glavine	305	0	22	1.000	.000	479	479	2.51	1,937	50	25	0	3276.0	2,844	913	1,013	205	987	41	0	80	13,287	39	5.32	2.71	1.96	0.56	14.6	7.4	1.17	.261	2.78	7.81
13	Randy Johnson R. Johnson	303	0	22	1.000	.000	452	437	2.41	3,775	75	37	2	3138.2	2,282	841	929	243	990	130	7	17	12,544	67	10.82	2.84	3.81	0.70	30.1	7.9	1.04	.275	2.66	6.54
14	Early Wynn E. Wynn	300	0	23	1.000	.000	447	379	2.41	1,660	224	49	15	3111.0	2,525	834	928	177	1,096	42	57	11	12,691	35	4.80	3.17	1.51	0.51	13.1	8.6	1.16	.242	2.68	7.30
15	Lefty Grove L. Grove	300	0	17	1.000	.000	475	338	2.57	1,817	243	35	54	3045.2	2,757	870	1,008	105	867	28	104		12,581	40	5.37	2.56	2.10	0.31	14.4	6.9	1.19	.272	2.98	8.15
16	Tommy John T. John	288	0	26	1.000	.000	529	472	2.46	1,645	129	46	3	3433.1	3,122	937	1,067	174	814	67	22	48	13,859	108	4.31	2.13	2.02	0.46	11.9	5.9	1.15	.264	2.80	8.18
17	Bert Blyleven B. Blyleven	287	0	22	1.000	.000	442	437	2.29	2,538	167	60	0	3339.1	2,742	851	956	216	843	83	1	30	13,336	67	6.84	2.27	3.01	0.58	19.0	6.3	1.07	.262	2.58	7.39
18	Robin Roberts R. Roberts	286	0	19	1.000	.000	431	369	2.46	1,595	239	45	25	3108.2	2,676	849	929	257	536	36	44	26	12,312	22	4.62	1.55	2.98	0.74	13.0	4.4	1.03	.245	2.69	7.75
19	Fergie Jenkins F. Jenkins	284	0	19	1.000	.000	438	376	2.44	2,187	208	49	7	3070.0	2,551	831	928	263	583	49	32	52	12,162	37	6.41	1.71	3.75	0.77	18.0	4.8	1.02	.252	2.72	7.48
20	Jim Kaat J. Kaat	283	0	25	1.000	.000	661	408	2.71	1,801	147	31	17	3282.1	3,100	989	1,151	236	711	71	92	73	13,422	87	4.94	1.95	2.53	0.65	13.4	5.3	1.16	.270	3.16	8.50
21	Red Ruffing R. Ruffing	273	0	22	1.000	.000	399	326	2.79	1,336	228	45	18	2820.0	2,461	873	990	120	922	30	57		11,616	30	4.26	2.94	1.45	0.38	11.5	7.9	1.20	.254	3.16	7.85
22	Mike Mussina M. Mussina	270	0	18	1.000	.000	384	383	2.60	2,138	44	23	0	2659.2	2,270	767	819	213	527	37	0	14	10,515	43	7.23	1.78	4.06	0.72	20.3	5.0	1.05	.271	2.77	7.68
23	Burleigh Grimes B. Grimes	270	0	19	1.000	.000	404	304	2.51	1,089	236	35	17	2856.0	2,658	796	978	80	784	53	78		11,790	54	3.43	2.47	1.39	0.25	9.2	6.6	1.21	.263	3.08	8.38
24	Jamie Moyer J. Moyer	269	0	25	1.000	.000	487	432	3.24	1,757	24	10	0	2918.0	2,726	1,052	1,121	296	758	95	13	38	12,061	34	5.42	2.34	2.32	0.91	14.6	6.3	1.19	.265	3.46	8.41
25	Jim Palmer J. Palmer	268	0	19	1.000	.000	406	373	2.15	1,675	166	53	4	2972.1	2,292	709	793	184	917	24	13	14	11,843	59	5.07	2.78	1.83	0.56	14.1	7.7	1.08	.233	2.40	6.94