Table:
text: 1955 Indianapolis 500
Classification
Classification
Grid Constructor_ Qual Rank_ Laps Time_Retired
25 Kurtis Kraft - Offenhauser 138.06 25 196 +4 Laps
32 Trevis - Offenhauser 134.44 32 196 +4 Laps
20 Epperly - Offenhauser 138.7 24 191 +9 Laps
21 Phillips - Offenhauser 139.86 14 178 Transmission
9 Kurtis Kraft - Offenhauser 140.3 4 170 Accident
24 Kurtis Kraft - Offenhauser 138.75 23 168 Engine
31 Trevis - Offenhauser 135.01 31 142 Transmission
6 Kurtis Kraft - Offenhauser 140 10 134 Transmission
28 Schroeder - Offenhauser 136.04 28 120 Fuel Pump
27 Kurtis Kraft - Offenhauser 136.8 27 119 Magneto
13 Pawl - Offenhauser 140.11 8 112 Ignition
23 Kurtis Kraft - Offenhauser 139.2 20 111 Engine

text: 1955 Indianapolis 500
Classification
Classification
Grid Constructor_ Qual Rank_ Laps Time_Retired
11 Kuzma - Offenhauser 140.16 6 90 Fuel Pump
5 Kurtis Kraft - Offenhauser 141.07 3 56 Died in crash
3 Kurtis Kraft - Offenhauser 142.58 1 54 Magneto
22 Kurtis Kraft - Offenhauser 139.55 17 54 Accident
30 Kuzma - Offenhauser 135.04 30 53 Accident
26 Kurtis Kraft - Offenhauser 136.98 26 53 Accident
29 Kurtis Kraft - Offenhauser 135.33 29 53 Retirement
1 Stevens - Offenhauser 140.04 9 40 Oil Leak
4 Kurtis Kraft - Offenhauser 141.93 2 39 Spun Off
15 Pankratz - Offenhauser 139.99 12 10 Engine

Question: What is the smallest grid with a Time/Retired of Engine and an agony of less than 138.75 in the 1955 Indianapolis 500?