Dropped the engine today in my 70 ST clone racecar. While buried in the engine compartment, I noticed that the weber IDAs actually have the S stamp on the ends of the carbs. Not what I was expecting. The engine is completely sorted, and I am reticent to replace the carbs with other IDAs I have on the shelf. Question is ...what is the value differential between non-S IDAs and S IDAs. And what is the performance differential.
Speedo