BWFitz

I've been running my 67 C10 here in the desert for about 10 years now. Because it's the desert and the density altitude fluctuates between 1000 ft and 6000 ft I have been re-jetting the Holley 4150 four times a year just to keep it fromm running like crap. I decided to convert it over to a Holley EFI system to avoid all the hassle but there was only one manifold to fit my 572...a low rise Edelbrock unit that I did not want so I went to Chevrolet Performance and ordered a 502 injection manifold, a set of Weiand manifold spacers and installed it. Now it has the throttle response I wanted, works well winter or summer and I am a happy man! Runs like this:

Racer86

Great job, ecu is the way to go even for older engines. Some of the new aftermarket EFI will tune themselves with a wideband O2 sensor

BWFitz

Thanks! The Holley ECU I used does tune itself but not at idle. You have to get a good stable idle then drive a bit to allow the ECU to tailor AFR and timing. Learning rate is fast and adjustments seem to be near optimal.