I had the pro jection 4 4 barrel 900 cfm unit..
The first ones, with analog ecu control are very basic..
the later ones with digital computers are said to be better.. but still very basic..
I bought my pro 4 in 93. if you are looking for power pass
if you are looking for set it and forget it, then it might be worth looking into..
remember that unit listed in ad was for the 80-90's 454 trucks motors..
I'd get the part # from the seller and find out what one it is, holley made a few different ones, and then the difference in the computers..
the analog ecu has dials that control the set up, that's how you tune it, turning dials on the end of the computer,