72 T500 carb weirdness (long post, early vs late carbs)

[m in sc]

fast forward a few yrs..on the 2nd t500,,i was also trapped with stock early carbs. i had a bunch of spare parts, but all early internal vented bodies. so i compared and the only difference seemed to bethe lack of an external vent, so I made one. drilled and removed a brass ball from a cross port and fit a 188-p4 jet tube and 5fp17 needle,  stock for 73 and up. viola! carburation, sorted.  this one will stay stock (the 71) but its just dismal the factory setting pre 73. the current replacement is a 159-p4 jet tube,  but these require a,hex jet vs round. as an fyi. however, what im going to do is retrofit a set of vm34s i have for the black 72. endless... lol.

[teazer]

I was under the impression that a 188 is the round jet equivalent of a 159 series. That's according to my measurements and notes.

For some reason I have a dyno chart that suggests that early carbs made more low end and later ones made more at peak, but I have no details of the tests.

[m in sc]

correct on the jet tubes.  as far as the torque,  having literally just done it back to back if its anything, it's the change in the later motor intake length or airbox. my 0.02