Navajo rating

[TwinNDB]

T - Turbocharged
I - Injected
O - Horizontally Opposed

Got these from 100LL a while ago when I asked a question in Engineers and Tech's:

Example: TIO 540 E1B4D
PREFIX
L - Lefthand Engine Rot.
T - Turbocharged
V - Vertical Helicopter
H - Horizontal Helicopter
A - Aerobatic
I - Fuel Injected
G - Geared Nose Section
S - Supercharged
O - Opposed Cylinder

Middle 3 Numbers are Cubic Inches

SUFFIX
E - Power Section & Rating
1 - Nose Section
B - Accessory Section
4 - Counterweight Applic.
D - Dual Magneto

and these from HeliEng:

Straight from the mouths of Lycoming, here we go!

1. Prefixes

AE - Aerobatic (wet sump)
H - Horizontal Helicopter
I - Fuel Injected
L - Left Hand Rotation Crankshaft
O - Opposed Cylinders
T - Turbocharged

2. Cylinder Cubic Inch Displacement

Cubic Inch Displacement No of Cylinders

235, 320, 360 4
540, 580 6
720 8

3. Suffixes

L - Indicates change in Power Section and
Rating from Original Design
1 - Indicates Nose Section
B - Indicates Accessory Section
5 - Indicates Counterweight Application