...larger idle jets. Back to the symptoms, in case anyone has similar problems. The car is a '76 GT4. Car was crackling/popping and backfiring on deceleration and the rpm wouldnt drop when I shifted. My idles were 45 and my mains were 130. The car came with a set of 135 mains and I ordered some 50 and 55 idles. I put in the 135 mains and the 55 idles and everything is cured. I understand that the original leaness was due to too small idles, but I can't figue out what caused the rpm to stay high when shifting. Go figure. If anyone is interested in some 45 and brand new 50 idles as well as some 130 mains, let me know or make an offer on some or all.
Doug, great info! What your plugs for loading up....I know when I richened my main jets, I needed to go up one heat range on the plugs to keep from fouling...I think I was using a NGK 6, but the car needed a 5. But I went up several sizes...they are 125s on a 78-79, and I went to a 140. Dave
Philip, how does it run rich on smaller jets when I close the throttle. That is what confuses me. I put in larger idles and that cleared up the problem. Dave, I am running Champion N9Y's based on some advice from this board gapped at .26. I also have a single dist. electronic conversion with a Mallory Unnilite ignition.
Hey, that's what happened to my car too! Previous mechanic installed 45's for whatever reason. Car stumbled alot when pulling away from stops. Put in the correct 55's and beauty since.
Doug - am looking at a Mallory Unilite single distributor as well - who did yours and what did your best advance settings turn out to be? many thanks Russ
Russ Mine is a homke fabricated unit by the PO. He used an original distributor and then fabricated it to accept a UNilite ignition and a Mallory cap/rotor. I am out of town for a few days, but I can get you the part numbers when I get home if you would like. I set the advance at 1000rpm to 7deg. I can't recall the higher rpm advance off the top of my head.
