I think 48s or very early 60s.
Shermans did burn well though.
Only the early Shermans pre-wet storage and other measures, and even that was over-exaggerated. That stupid Death Traps book has long since been debunked by Zaloga and the War Department/DOD archives among many others.
https://en.wikipedia.org/wiki/Death_Traps#Reception
Cooper’s duties had him looking at a disproportionate number of losses and he extrapolated his area of observation to the entire fleet - and that just turned out to be wrong. The actual crew casualties was .5-1.5 soldiers lost per hull loss - I don’t recall the exact number.
Even the early Shermans didn’t actually burn at a statistically significantly higher rate.
https://en.wikipedia.org/wiki/M4_Sherman#Effectiveness
A Waffenamt-Prüfwesen 1 report estimated[90] that with the M4 angled 30 degrees sidewards, the Sherman’s glacis plate was invulnerable to shots from the Tiger’s 8.8 cm KwK 36 L/56[91] and that the Panther, with its 7.5 cm KwK 42 L/70, would have to close in to 100 meters (110 yd) to achieve a penetration in the same situation.[92] Although the later-model German medium and heavy tanks were greatly feared, Buckley opined “The vast majority of German tanks encountered in Normandy were either inferior or merely equal to the Sherman.”[93]
Research for tank casualties in Normandy from 6 June to 10 July 1944 conducted by the British No. 2 Operational Research concluded that, from a sample of 40 Sherman tanks, 33 tanks burned (82 percent) and 7 tanks remained unburned following an average of 1.89 penetrations. In comparison, from a sample of 5 Panzer IV’s, 4 tanks burned (80 percent) and 1 tank remained unburned, following an average of 1.5 penetrations. The Panther tank burned 14 times (63 percent) from a sample of 22 tanks and following 3.24 penetrations, while the Tiger burned 4 times (80 percent) out of a sample of 5 tanks following 3.25 penetrations.[94] John Buckley, using a case study of the British 8th and 29th Armoured Brigades, found that of their 166 Shermans knocked out in combat during the Normandy campaign, 94 (56.6 percent) burned out. Buckley also notes that an American survey carried out concluded that 65% of tanks burned out after being penetrated.[95] United States Army research proved that the major reason for this was the stowage of main gun ammunition in the vulnerable sponsons above the tracks. A U.S. Army study in 1945 concluded that only 10–15 percent of wet stowage Shermans burned when penetrated, compared to 60–80 percent of the older dry-stowage Shermans.[96]
A high school friend of mine commanded a M60 in the 1980’s when they were just beginning to get the M1’s in Germany.
He got out on a medical before he could get in to a M1.