New Holley spreadbore FI

My buddy ran Holley's FI on a blower motor and it would not work
and here is why, he had a 4 speed lenco and when he would cruise down the road and grab the next gear he never gave it more gas and with the extra load on the motor it would lean out and pop back and throw the belt every time. Holley sent him many calibrations and none would work. He went back to 2 4 bbl's and it never happened again.
General information there. What Holley efi, what year was it made? Early model? The Lenco is a racing trans suggesting a race car. The above Holley FInis obviously (IMO) a replacement style low power unit.

What does throwing belts have to do with anything? LOL!
Holley sent him calibration mods? These are self learning.
Your casting a shadowy doubt based off another’s experience of how long ago on a older system?