Most Home Runs 1971-1973 and 1966-1973.

Hank Aaron aged well.

Rk	Player	HR ▾	From	To	Age	G	PA	AB	R	H	2B	3B	RBI	BB	IBB	SO	HBP	SH	SF	GDP	SB	CS	BA	OBP	SLG	OPS	Pos	Tm
1	Willie Stargell	125	1971	1973	31-33	427	1784	1528	285	452	97	5	356	228	57	412	12	0	16	21	1	1	.296	.388	.611	.999	*73	PIT
2	Hank Aaron	121	1971	1973	37-39	388	1583	1336	254	399	44	4	291	231	49	164	4	0	11	33	6	2	.299	.401	.609	1.010	3/97	ATL
3	Bobby Bonds	98	1971	1973	25-27	468	2126	1888	359	522	95	13	278	209	19	422	14	1	14	31	113	31	.276	.351	.496	.847	*9/8	SFG
4	Lee May	96	1971	1973	28-30	443	1839	1690	237	469	72	8	301	128	24	402	8	0	13	39	7	2	.278	.329	.500	.829	*3	CIN-HOU
5	Johnny Bench	92	1971	1973	23-25	448	1917	1657	250	420	58	7	290	232	44	250	2	1	24	60	12	8	.253	.342	.463	.805	*2/9375	CIN

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 1/23/2013.

Aaron has by far the fewest at bats (AB) but the second most home runs (HR) 1971-1973.  All five batters are in the National League (NL) so to compare you can just get a ratio between AB and HR.  Aaron should lead.

Notice the ages.  Aaron is older by six to 14 years.

The Braves moved from Milwaukee to Atlanta in 1966 where Aaron played in a home park more conducive to HR hitting than his previous park.  Here are the top HR hitters 1966-1973.

Rk	Player	HR	From	To	Age	G	PA	AB	R	H	2B	3B	RBI	BB	IBB	SO	HBP	SH	SF	GDP	SB	CS	BA	OBP	SLG	OPS	Pos	Tm
1	Hank Aaron	315	1966	1973	32-39	1158	4853	4208	771	1243	193	16	828	595	140	529	10	0	39	106	90	26	.295	.381	.573	.954	*93/784	ATL
2	Willie Stargell	262	1966	1973	26-33	1110	4488	3906	639	1118	209	21	775	495	134	968	38	8	41	76	10	5	.286	.369	.552	.920	*73/9	PIT
3	Harmon Killebrew	249	1966	1973	30-37	1099	4557	3674	579	952	139	11	741	826	113	693	16	0	41	132	12	10	.259	.394	.506	.900	*35/7D	MIN
4	Willie McCovey	248	1966	1973	28-35	1050	4197	3442	565	976	159	21	724	684	183	602	31	2	38	65	10	8	.284	.403	.558	.961	*3	SFG
5	Dick Allen	238	1966	1973	24-31	1030	4329	3710	666	1096	185	46	711	577	104	966	10	5	27	89	85	36	.295	.389	.563	.952	357/468D	PHI-STL-LAD-CHW
6	Frank Howard	238	1966	1973	29-36	1122	4456	3864	518	1058	143	15	653	548	105	833	22	0	23	150	5	5	.274	.365	.503	.869	*73/D9	WSA-TOT-DET
7	Billy Williams	235	1966	1973	28-35	1274	5546	4946	776	1469	224	52	798	531	110	491	24	2	43	110	40	19	.297	.365	.506	.871	*79/3	CHC
8	Frank Robinson	228	1966	1973	30-37	1077	4527	3817	681	1110	178	19	701	597	72	621	70	2	41	118	38	18	.291	.393	.527	.919	*97D/3	BAL-LAD-CAL
9	Carl Yastrzemski	209	1966	1973	26-33	1226	5236	4384	731	1265	223	18	721	801	83	538	14	2	34	106	91	61	.289	.397	.491	.888	*73/58	BOS
10	Lee May	204	1966	1973	23-30	1052	4302	3974	546	1094	204	17	652	264	51	863	32	3	29	101	21	23	.275	.323	.489	.813	*3/79	CIN-HOU
11	Ron Santo	200	1966	1973	26-33	1228	5186	4409	676	1238	185	31	766	686	57	759	23	7	61	149	17	23	.281	.376	.473	.849	*5/674	CHC

Provided by Baseball-Reference.com: View Play Index Tool Used
Generated 1/23/2013.

Aaron has by far the most HR but the fourth most AB, exceeded by the two Cubs and one Red Sox.  Reggie Jackson had 189 HR and Willie Mays 155 during those seasons.  Aaron is at least two years older than any of the ten other batters with at least 200 HR 1966-1973.