1967 Shelby Mustang Tuning

We at Innovate were recently contacted by an owner of a beautiful 1967 Shelby Mustang. After having done some engine work to his almost completely restored car, it started to run really rough when at higher RPMs, and particularly at WOT.

On the LM-1, the results were as follows:

RPM	Left exhaust	right exhaust
Idle	0.9	0.9
1000	0.78	0.79
2000	0.79	0.82
3000	0.85	0.84

But what was really interesting was that when he opened it up, just momentarily (2-3 seconds) and the secondary barrels of his four barrel carbs opened, lambda ran up to between 1.3 and 1.7. This corresponds to what he was seeing with the rough running of the engine when the secondaries were opening. We took this information to his tuner, who confirmed that the secondaries were not jetted properly, resulting in a lean condition. This was corrected, and the car is now running well