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I took a 5.8 EFI from a 1993 F250 and installed it into my 1973 Ranchero. I purchased a Lightning intake so I could close the hood. I converted the engine to Mass Air. I used Ron Francis wiring Telorvek IV system to wire in the ECM. In doing this I also deleted the EGR and the solenoids. Was this a good idea? I have a whistling sound at idle and low rpm. I did not plug the small center hole in the plenum, should I have? The noise seems to be coming from the center tubes of the plenum. It is an OBD1 system and I have no codes or engine light on. Francis also supplied a bypass kit for the EGR elimination. Also, the cannister purge, air divert and air bypass solenoids have been eliminated. Thanks for any insight.
I took a 5.8 EFI from a 1993 F250 and installed it into my 1973 Ranchero. I purchased a Lightning intake so I could close the hood. I converted the engine to Mass Air. I used Ron Francis wiring Telorvek IV system to wire in the ECM. In doing this I also deleted the EGR and the solenoids. Was this a good idea? I have a whistling sound at idle and low rpm. I did not plug the small center hole in the plenum, should I have? The noise seems to be coming from the center tubes of the plenum. It is an OBD1 system and I have no codes or engine light on. Francis also supplied a bypass kit for the EGR elimination. Also, the cannister purge, air divert and air bypass solenoids have been eliminated. Thanks for any insight.
If you truly deleted the EGR system, and you're not using smog heads, then there is no need in plugging the center port on the lower intake.
Another thing with deleting the EGR is that you need to make sure all of the vacuum lines have been plugged as well. Disconnecting the electronics will not hurt anything.
Install looks great BTW!!!
Last edited by Blurry94; Nov 13, 2025 at 08:00 PM.
If you truly deleted the EGR system, and you're not using smog heads, then there is no need in plugging the center port on the lower intake.
Another thing with deleting the EGR is that you need to make sure all of the vacuum lines have been plugged as well. Disconnecting the electronics will not hurt anything.
Install looks great BTW!!!
Ok, Thanks! Yes, we used heads from mid 60s (larger exhaust valves if I recall correctly.) Wonder what is causing the whistle sound then? Not a vacuum leak. First, I thought maybe a bearing on the idler pulley but then I removed the belt but still had the noise. Using a stethoscope, we narrowed it down to the center of the tubes on the plenum.
