Holley TBI

I have had the "2 injector" Holley Pro-jection on my 65 Newport (383) since 1996, using both the "analog" box and the smaller "2D digital" box. My impression is that the original "by MSD" box would be more reliable since it uses rugged Weather-pack connectors. Holley brought the design in-house after that and botched it a bit, as they do most electronics projects. Their analog box has a small connector that can be erratic. One wire pulled out of mine and I saw it was barely crimped to the terminal (thick wire). The 2D box uses the same connector and adds the problem that it overheats and starts limiting fuel. Don't let the sun hit it. Some people have had it melt their vinyl seats. You are tempted to keep the box on the seat because seems you must constantly tweak the knobs. I have O2 feedback, but usually run that just as a monitor and tweak manually because I don't trust the box. I have plans to fix Holley's errors, but don't drive that car currently. Its biggest design issue is that it uses only throttle position to "infer" manifold pressure. You really need PMAN and IAT sensors for a decent fuel controller (or a mass-flow sensor).

What's it worth? People still ask $500 on ebay, especially for the 4 injector versions, but I wouldn't pay that. I was a fool to have paid retail for it (~$600) in 1996 dollars, and it never gave the mileage improvement I hoped for. I think their last-gasp 4Di version added the needed sensors and essentially became their Commander 950, which is a much better design (have some to try). Those went for $600 on ebay lately, but now that their is a new $1000 TBI (above), that will change.