Newly rebuilt 383 running rich

[Dad's69RR]

Ok here is the short. Just purchased 69 Roadrunner and it has newly rebuilt original 383 bored 0.30 over. I do not know what cam was put in it and guy upgraded to electronic ign and threw on an Eldebrock carb out of the box. The car is still cold natured but when running it is running extremely rich. I do not have a timing light but should I try advancing the timing first? I know the carb needs adjusted but do not want to mess with until I know timing is right? I haven't adjusted timing yet because hard to do when I have to keep car running so need another guy to help. Also would it be a good idea to drain oil and replace even though it looks clean. I guess the question is what I should do first since I just purchased the car?

 

[lewtot184]

some of the edelbrock carbs have .093" needle and seats and won't take much over 6psi fuel pressure. some are calibrated rich and need to be recalibrated. low vacuum from a longer duration cam may cause the metering rods to be too far out of the jet for low speed operation. it's always best to get the ignition right before going after the carb but you may not have that luxury. carb type and manifold vacuum readings would be very helpful. 383's are very sensitive to high overlap cams and generally are not recommended for street use.

 

[Rich Kinsley]

Ok here is the short. Just purchased 69 Roadrunner and it has newly rebuilt original 383 bored 0.30 over. I do not know what cam was put in it and guy upgraded to electronic ign and threw on an Eldebrock carb out of the box. The car is still cold natured but when running it is running extremely rich. I do not have a timing light but should I try advancing the timing first? I know the carb needs adjusted but do not want to mess with until I know timing is right? I haven't adjusted timing yet because hard to do when I have to keep car running so need another guy to help. Also would it be a good idea to drain oil and replace even though it looks clean. I guess the question is what I should do first since I just purchased the car?

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Don't even think about using the Service Manual for tuning specs. Unless it is stock it doesn't pertain. #1 issue with the carb may be fuel pressure. The Eddy carbs are superb but they can only use 6.5psi MAX. If you are over that you will bend the floats and it will gush gas all over the place. Been there, done that. Get a fuel pressure regulator if needed.

Hook up a vac gauge to the driverside front port of the Eddy and adjust the dist for max vac and highest smooth idle. Then set the idle to what you want and check with a timing light to see where you wound up. If you ping when accelerating under load then set it back a tiny bit till it quits. This should be what your engine wants.

Use the Edelbrock manual and check the float levels, etc per data/instructions in the manual. If you don't have one they are available. They are a very simple carb to tweak and do not need to be removed from the car to accomplish almost all changes/repairs. There is a chart in the manaual that will walk you through the changes to richen or lean as needed. Usually out of the box they are quite driveable. I assume you have the electric choke model? Got it hooked to a key on source?

Sounds like you have a nice car. Enjoy.

 

[Dad's69RR]

Thanks Rich I will try tonight and let you know results.

- - - Updated - - -

Unfortunately it is a manual choke model!

 

[Dad's69RR]

Ok finally got to spend some more time trying to get RR running right. At first could not get the car to run unless it was advanced 25 deg! Found a loose connection to number one cylinder so once that was fixed the idle smoothed out around 10 deg but would get a backfire through the carb when opening up the throttle. I think there maybe a couple of problems, the mechanical advance would advance too soon and for some reason running lean even after carb was adjusted. I pulled the distributor and found a spring missing from the mech advance, now I know this used to be a trick by the drag racers to remove one of the springs but this isn't going to be a drag car. Does anyone have an opinion on the vacuum advance whether I should leave it or not? In the past I have always taken them off. I know it will be difficult to start but it seems like it is always difficult to start. I am going to pull the carb and clean and make sure nothing is gummed up. The carb is a 1407 Eldebrock 750cfm, any other suggestions? BTW what is the circumference of the harmonic balancer?

 

[eagleone1983]

I don't have an answer to the harmonic balancer but in regards to your timing. If the engine isn't stock, which it isn't since you think there may be a cam change, it's been worked over (.030 bore), and possibly other things 10* advanced may not be enough timing. I'm running 19* because that's what my engine wanted probably could give it even a few more degrees but I left it at 19* to avoid any pinging. If I went down to 10* she'd probably not run very well at all.

 

[440beep]

For a daily driver/cruiser you should leave the vacuum advance, just need to learn how to adjust it. Once you get the car driveable and can take it for a cruise you need to hold a steady mph like 35 and pay attention to how the car is cruising. Do you feel it surging, it should be very slight but should still be able to feel it? If so, you need to turn the vacuum advance down in small increments until the surging stops. Or conversely, if no surging initially, perhaps advance the vacuum advance until the surging starts then back off a lil bit.

I forgot the size of the allen wrench that's needed for the adjustment nut in the vacuum cannister.



For more info, run a search on "vacuum advance" in the "search" box and see all the results, especially all the ones that recommend running vacuum advance on a street driver.

 

[Dad's69RR]

Have any of you guys used the ProForm distributor? Have heard some negative feedback but will know more when I finish rebuilding the carb and get the car running right. I couldn't believe it, but the primary jets were in the secondary ports and both needles were worn out! Owner not that honest about pulling out of the box and putting on the car! Think I will keep the vacuum advance.

 

[brasil]

..the allen wrench should be a 3/32 ...afaik

.Greetings Juergen