what is meant by last letter in primary metering rods numbers

[Frank400]

I'm talking late model carbs here, '76 and up APT models.  I know what a 41, 42, 43 etc rods are.  I know some of them have a .036" tip, the others have a .026" tip.  But what does the P, K,M etc mean ?  Is it the taper style ?

   Frank.

[Ethan1]

I'm talking late model carbs here, '76 and up APT models.  I know what a 41, 42, 43 etc rods are.  I know some of them have a .036" tip, the others have a .026" tip.  But what does the P, K,M etc mean ?  Is it the taper style ?

   Frank.

 The letter code at the end of the two numbers, denotes whether the rod is single or double taper and diameter of tip. "M" rods were double-tapered, w/ .032" diameter tip, "P" rods were double-tapered w/ .026" diameter tip, etc....

[Frank400]

Thanks for the info, Ethan, but I only mentioned M, P and K, but are there any others that I should know about ?  What about the configuration of the K rod ?

[Ethan1]

Thanks for the info, Ethan, but I only mentioned M, P and K, but are there any others that I should know about ?  What about the configuration of the K rod ?

 "A" rods were single-tapered, .026" diameter tip.
 "B" rods were double-tapered, .026" diameter tip.
 "C" rods were double-tapered, .026" diameter tip.
 "D" rods were double-tapered, .036" diameter tip.

 on and on.....

 "K" rods were double-tapered, .026" diameter tip as well.

 There were several over the years.

[Frank400]

Wow !  thanks for the info.

  Frank.

[Ethan1]

 Not a problem. I also believe there were some triple-tapered rods as well. Just cannot remember which.