'69 Coronet 500

[Landon]

Hey guys,

I'm looking for advice on my car.

Here's what I got: 69 Coronet, 3500lbs, 727 torqueflight, 3.23:1 suregrip, 440 with mild cam, .40 over, edelbrock performer 440 intake, stock heads, stock exhaust manifolds, holley fuel pump regulated to 5-6 psi, MSD mechanical/vacuum advance distributor with 6A ignition and HSV2 coil, and a Holley 750 DP.

Here's my problem: If I ease into throttle the car is crisp and will smoke the tires when the secondaries come open:headbang:. If I stomp on it when the car is rolling or already has some RPMs same thing, it will take off:hello2:. However, When I stomp on it from a dead stop the car will die and/or bog until I let off the gas:icon_cry:. I'm pretty sure its carb related so I ordered a tuning kit (squirters, jets, power valves, pump cams). What carb setup would my car need??? Is carb too big/too small??? Or is this unavoidable with a DP on a heavy auto car with 3.23 gears out back???

Help is greatly appreciated,
Landon

 

[terzmo]

750 on that 440 is fine. Carb issue is my opinion. I run proform carbs on my cars...cheaper than a holley...same performance...more features..how old is the carb?? I would replace or at the least just rebuild it. A properly rebuilt 750 on that car should not display the issues you have.

 

[Landon]

I bought the Holley new less than 6 months ago. I was thinking it was too big/small, I need someone with carb tuning experience/knowledge to give me some tuning advice on which jets, squirters, pump cams, and power valve to use for my setup? Also I set my timing to 38 degrees total, inside the distributor I changed the bushing to the one that allows most advance, and I also changed the springs to the ones that allow it to get there the quickest. Is this correct? Is 38 degrees total too much?

 

[YY1]

Have you tried more pump shot?

 

[Landon]

I have the brown pump cams on right now with the biggest squirters but it still bogs when I floor it. If I'm rolling slow and floor it, it will hesitate then go

 

[Brandy]

YY1 your PM message box is still full buddy. Paypal is fine. $100.00 sound right? Ghost

 

[Landon]

Yeah I went up on the shot and the pump cam, still has a bog

 

[Coronet 14]

Vacuum leak at intake or carb?

 

[Landon]

no, none that i can tell anyways

 

[Garys1969RR]

You are prob dumping too much air/fuel at a low RPM. A higher stall T/Converter would help. Or a vac secondary would prob work better on an auto. I have a 780 vac secondary-3310 Holley on my 440 1969 Roadrunner , and it always catches and goes even from a dead stop. But I also have a higher stall T/C, and 4.11 gears. Most engines have to have a little RPM before you can give wide open throttle.

- - - Updated - - -

And I like to run 20 degrees initial advance, 38 total. These motors seem to like alot of initial spark advance. Have you limited your dist advance to 18 crankshaft degrees? You can do that with a special plate you put in there above the weights, or by welding the slots up to make them shorter.

 

[YY1]

What are you calling a "mild" cam?

I've had people tell me a 284/484 is "too big" and other people say a 513 lift is "small".

I ran the 284/484 with a stock converter and it was a terrible bitch to find the right carb for and tune, but when I finally got it dialed in it was just fine except for that hollley 200 rpm idle drift from week to week.