Edelbrock 1407 off idle bog
- Thread starter Baker7888
- Start date
Ok the 600 is on. Its raining so i havent road tested yet. First notes are, idle vaccum is about 2” higher. However screws are out almost 5 turns. The idle hangs a just a touch which makes me think its lean. Checked for leaks, no leaks. It also idles higher. About 1100 rpm. Screw is all the way out. Cant get it to idle any lower. It does not diesel when shutting off. Checked float hang and drop, also checked jets, everything is baseline. I have a small hill in my driveway. Releasing clutch does about the same thing the 750 did. I still need to road test. But i took the 750 for a spin before the swap and it wasnt bad. I could live with that.
Agreed. Any ideas? Im thunking of putting the 750 back on. Maybe drill out idle jets more??
I guess I am not positive other than the fact that it has more idle vacuum than before. I did spray the carb base gasket and got nothing.
I rebuilt a 1405 years ago on a 358 with a huge cam and had what seemed like unavoidably high idle no matter what. 4.5 turns out on idlemix screws lowest could go and 1200-1000 rpm was best I got without retarding timing. Muscle car solutions or uncle tony had a video I saw recently about that "high idle" being some Edelbrock afb quirk and an explanation for it. Been following this thread man hope you can overcome!
I dont know what was going on yesterday but i decided to adjust the fast idle on a whim and it seems to be idling normally now. Its manual choke so really i was just getting the screw to fall in between the two lines on the cam, which i did by adjusting the cable slightly. Not sure how this helped drop the idle, but it did. It was not off by much and i have never needed the choke. I redid idle mix screws from scratch and they are now about 2-1/4 turns out at about 15” wg, which is about where the 750 was. Idle screw is backed out all the way but the idle is normal, even low. I did change the silver springs to orange, and verified while running they are staying down. They come up with blip of throttle. I checked all lines, carb mating surface, intake, brake booster with propane and could not detect any vacuum loss. It’s still pouring here, i’d prefer not to take the car out and get it all nasty. It did not however seem to shudder in the driveway (not really a good test tho) so just watching the weather at this point .. wondering if it still shudders, would trying the drilled out idle jets from the boosters off the 750 be worth the time?
Ok i took it out. Takeoff does seem to have improved, but not perfect. Low-Mid range seems smoother as well, but possibly feel like maybe a slight power loss, that could be in my head as well. Secondaries hit hard, same as 750.
After I drilled the idle jets on the 750 there was a good improvement in takeoff. Its hard to tell if it was as good as the 600. It was close. I could probably get used to either one. I am pretty sure at this point it is probably over cammed a touch and that is something i am willing to live with. Repop clutch pedal geometry may be off a touch as well.
My main concern right now is, am i leaving any power on the table by running the 600 instead of the 750?
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