,All front and rear plates are either # 199 or # 226,big block,the # 199 is big block only and has a smaller hole than the # 226,small block is # 226. The # 199 plate was used as replacement due to supposedly sticking # 226 in early production but not sure of when the change was made,most all I get in have the #226 plate.I have all the original Chrysler engineering,installation,specifications and adjustment procedures from 1970,I'll go through it when I get a chance and possibly clear things up a bit. If you don't have and can find one of these Holey manuals buy it,you'll never need to second guess anything,it's all in there.

.Below is metering block application and blades,no exceptions .


# 6170 69 1/2 A12 225 throttle blade
# 6020 70/71 440-6 222 throttle blade
# 6610 70 AAR/TA 222 throttle blade