[D/FW RX-7] Hawk brake pad ID

[FrankenRex (Kevin Wright)]

I won an auction on eBay for a set of Hawk brake pads for the rear of  
my 7. Problem is, I have no idea what compound they are.
The box says;
Hawk Brake
HB158
Y-5
EXP

The pads them selves say:
HAWK BRAKE
HB158 Y 5
BURNISHED

paint on the backing plate is black.

They're definitely a semi-metallic.

Any ideas?
IF Y is the compound, that's the "LTS Light Truck and SUV" compound,  
which is silly, since the HB158 only fits RX-7s...

Kevin Wright                                                
FrankenRex at sbcglobal.net
Dallas/Ft. Worth, TX                                   http:// 
www.wankel.net/~krwright/cars/rx7/rx7.html

1980 and '85 Factory Service Manuals, 1979-85 RX-7 Wiring Diagrams,  
and all years' Parts Catalogs scanned and on-line at
http://www.wankel.net/~krwright/cars/rx7/manuals.html

A bucket-load of first gen '7s, and a '70 Olds Cutlass named Snoopy