I have a truck with a new 460 motor. The motor has a real bad bog off of the bottom, and if you try to accelerate quickly from a low RPM, it will backfire in the carb. Once you get her into a higher RPM range, it runs good, but wants to ping a little bit under load.

I am a diesel guy, and would like to learn to tune this motor on my own instead of taking it to a shop which is why I am posting on here to try and get some help.

The motor had some initial setup done by an educated backyard mechanic.

The motor has about 700 miles on it now, and here are the specs on it:

Motor 1993 460,
new crank,
.010 over pistons,
block all machined,
heads planed and Inconel valves..
new stock cam,
Stock injected manifold( injector ports blocked),
Edelbrock 650 carb
headers


Can you guys give a couple things to look into to get me started in working this out, or if there is more info I need to provide, let me know what it is.

Thanks for the help. I'll report back as I work through this.

 

I should add that the carb, ignition, headers, fuel pump is all brand new as well, so generally speaking, that should eliminate malfunctioning of these parts are the cause of the problem.

I just downloaded the manual for the edlebrock carb and am reading through that....maybe that will help some.

The truck will idle well, but as soon as you start to get on the gas, it will bog and want to stall and backfire in the carb. If you then quickly flutter the gas accelerator pedal, you can get through this and then when you get it up to 2k or so, it runs fine.

thanks again

 

sounds like the accelerator pump is not working or is set too lean. you have the book so that should tell you how to adjust for more fuel.

 

How did you tune the carb before?

 

I would say the same thing.

To the front right of your carb when you're looking at it on the engine you can see the accelerator pump. It should have 3 spots where you can put the pin through it to change the shot that it gets when you hit the gas.