Is my carb too big for my 383?

[734406pk]

Are you running at 12.5:1 compression ratio?

[Bluemonster71RT]

11:1

[734406pk]

Ok - 11:1 compression ratio. All the spark plugs but #5 have white electrodes- correct?

[Bluemonster71RT]

Currently freshly cleaned electrodes. #5 was wet until I l cleaned it. 

[734406pk]

Ok. Try number 78 or 80 main jets in the primary side. Use the black spring in the secondary vacuum pod to lock it out. Your power valve should be 1/2 your idle vacuum or less in drive. Set your total timing to 36-38 degrees all in by 3000 rpm. The base timing, 20-22 degrees BTDC or where it runs best, but keep the same total timing. Test run using 98-100 octane fuel if you can get some of that (would be great). Test run and see what happens! White plugs show high combustion chamber temps. Lean condition/too much timing or both. The AR 3933 is a mid-heat range racing plug. It should work for your engine.

[Strawdawg]

If you cannot find any high octane, set total timing to 32 degees and see if the problem persists

Sent from my LG-H810 using Tapatalk

[734406pk]

If you cannot find any high octane, set total timing to 32 degees and see if the problem persists

Sent from my LG-H810 using Tapatalk

 

[Bluemonster71RT]

I can get 110. The plugs weren't white just mildly sooty. The week before that they looked like I just put them in.
All in by 3000 is where I am now. I'll make sure I'm at 38 changw the jets and spring tomorrow and I'll let you know what happens.

[734406pk]

Ok good luck!

[jhaag]

Man you have chased your tail on this thing for quite some time. Made a lot of changes, non that worked. Your constant is the plugs if I am not mistaken? You need hotter plugs. Those autolite racing plugs run cool. You said they had a brownish "film or glaze" on the porcelain. Classic symptom of a plug not hot enough to burn off deposits, and cause misfire. This will cause the problems you are describing. Do yourself a favor and put in hotter plugs. I am sure the edelbrock tech line can get you close. I have been there. This will fix your issues.  good luck

[734406pk]

I can get 110. The plugs weren't white just mildly sooty. The week before that they looked like I just put them in.
All in by 3000 is where I am now. I'll make sure I'm at 38 changw the jets and spring tomorrow and I'll let you know what happens.

Check/reset the float levels as needed too.

[Bluemonster71RT]

Man you have chased your tail on this thing for quite some time. Made a lot of changes, non that worked. Your constant is the plugs if I am not mistaken? You need hotter plugs. Those autolite racing plugs run cool. You said they had a brownish "film or glaze" on the porcelain. Classic symptom of a plug not hot enough to burn off deposits, and cause misfire. This will cause the problems you are describing. Do yourself a favor and put in hotter plugs. I am sure the edelbrock tech line can get you close. I have been there. This will fix your issues.  good luck

I was told to get those plugs but I just looked up some info on them. They are best suited for 12.5:1-13:1. I wonder if thats why I have no issues at wot? I'm going to get some hotter ones right now before I make all the listed changes.

[734406pk]

I was told to get those plugs but I just looked up some info on them. They are best suited for 12.5:1-13:1. I wonder if thats why I have no issues at wot? I'm going to get some hotter ones right now before I make all the listed changes.

Spark plugs! You may be on to something! After a little digging, Edelbrock recommends Champion RC12YC. The Autolite equivalent is AR3924 Which is 4 steps hotter than your current AR3933. Also both the Champion RC12YC and the AR3924 have projected tip electrodes which may be required on these Eddy heads and they are both resistor type plugs.

[Bluemonster71RT]

I knew it was going to be something stupid. I bought the hotter plugs and because I knew that something was off with my $300 MAC tools  dial back timing light I bough a cheap digital one from Advanced.  It was off 21 deg. I could have done some serious damage My initial was at 42  . I put the new one at 20 and she purrs like a kitten. No pops, no chugs minor hesitation just before the secondaries open. (Maybe need to be  sooner?) Thank you 734406pk for sticking through this with me and to everyone else that helped out. Now I need some fine tuning to get this pig to rip some asphalt and mustangs.
 Oh and there IS something wrong with the edelbrock too. I put that on just to see and it is still a dog compared to the Holley. 

[734406pk]

I knew it was going to be something stupid. I bought the hotter plugs and because I knew that something was off with my $300 MAC tools  dial back timing light I bough a cheap digital one from Advanced.  It was off 21 deg. I could have done some serious damage My initial was at 42  . I put the new one at 20 and she purrs like a kitten. No pops, no chugs minor hesitation just before the secondaries open. (Maybe need to be  sooner?) Thank you 734406pk for sticking through this with me and to everyone else that helped out. Now I need some fine tuning to get this pig to rip some asphalt and mustangs.
 Oh and there IS something wrong with the edelbrock too. I put that on just to see and it is still a dog compared to the Holley.

Excellent news! Which plugs did you go with? I checked the Eddy instructions on the Performer heads and they recommend RC12YC Champion (or equal) as a starting point. Major difference is the heat range (+4 steps hotter)and projected tip electrode. Drain the fuel out of the Eddy AFB carb and save it for something stock to mild. They work fine for that application as thats what they were designed for. Now for the tuning of the Holley SA... Set up your float levels and lock out the secondary with the black spring. Jet the primary on the rich side to start with and work you way to lean checking sparkplug color.  Its safer that way. There are plenty of threads and Youtube videos on the process. Congrats!