Hello Dave,
When the Pinto was built, there was 100% gas at the pump.
now with 10% or more Alcohol the stock jets are too small.
Try putting the biggest jet in the primary side of the carb. and drilling the smaller jet to 1-2 sizes bigger than the one you have in the primary.
Make yourself GOOD NOTES so you can tune your Pinto to perfection.
The jets are located in the bottom of the fuel bowl the ones in the top are EMULSION TUBES and have an effect but are to introduce AIR into the fuel for proper atomization.
Any STOCK Pinto that is jerkey from the stop sign is most likely suffering from fuel starvation. Poping back throught the carb is a sure sign of a LEAN condition.
The numbers you might see in your carb depending on IF it is california emmissions or not, are 48 primary and 50-52 secondary.
From Pintony