454 surges when driving

[AJ 3]

My 1977 454 C 30 runs great and sounds great sitting in the driveway. As soon as I start driving down the road the engine bogs down and surges the more I press the accelerator pedal. Then once I shift into park sitting at home the truck run great again.

This has been going on all this year. I started replacing the basics cap, rotor, plugs, wires and fuel filters. I set my timing to 8 degrees before TDC and idle at 700 rpm. Still runs great in the driveway but crappy going down the road.

Only one day early spring it ran smoothly down the road. Once the engine reached operating temperature. I started hearing a ticking lifter. I found the intake lifter on #8 was collapsed. So I installed a full set of lifters.

During cleaning of my preformer edelbrock intake manifold I noticed it was cracked at the center heat rised. So I purchased and installed a edelbrock torker intake hoping to gain some low end torque.

Once again same story the engine runs great sitting in the driveway but crappy down the road.

Looking down the edelbrock carburetor I noticed that the accelerator pump was not squirting fuel when I moved the throttle. Carb rebuild time.

During my carb rebuild I noticed the floats were not set correctly, my secondary were opening to late, and my accelerator pump seal was distorted. After the carb rebuild the accelerator pump works great.

Still I have the same problem the truck runs great in the driveway but crappy down the road.

Help

 

[1973c10]

How is the fuel pump is it getting enough fuel running down the road

 

[AJ 3]

Thanks I did check the fuel pump. I disconnected the fuel line at the carb and cranked the engine. I got many squirts of fuel. If someone knows the gpm of a stock fuel pump I may be able to check the rate of flow at idle until my carb empty's of fuel.

Today I just fired up the truck and it ran really rough. So I pulled the plugs to see the condition. They all had a light coating of carbon which is ok because I have not really drove the truck since installing the new plugs.

Someone suggested I pull and plug the vacuum advance hose that runs from the carb to the dizzy and see what happens when I just run the mech advance. So I did and my timing dropped to 6 degrees before TDC. I reset the timing up to 12 degrees before TDC and went for a drive.

There was defiantly an improvement finally. The truck only spit and popped once and that is when I mashed the throttle. I drove for about 5 miles pulled into a parking lot and reconnected the vacuum line without checking timing. The truck ran worse then previously but still better than yesterday.

I believe my issue is either timing or dizzy related. So far the truck ran better but not as well as last year.

I am still confused.

 

[AJ 3]

I believe I have finally found the problem. I just swapped the dizzy from my 1979 daily driver truck that runs very good. Into the 1977 truck and poof the 77 finally ran good very good. I found out today that a 454 has tons of power. I kind of did not want to put the dizzy back into the 79 but I need to get to work tomorrow. So time for a new dizzy and I am thinking MSD.

 

[1973c10]

Glad you found the problem

 

[Jrgunn5150]

I believe I have finally found the problem. I just swapped the dizzy from my 1979 daily driver truck that runs very good. Into the 1977 truck and poof the 77 finally ran good very good. I found out today that a 454 has tons of power. I kind of did not want to put the dizzy back into the 79 but I need to get to work tomorrow. So time for a new dizzy and I am thinking MSD.

Is maybe the Vac Advance going nut's on you?

 

[AJ 3]

My truck is back to running like crap again. This time the truck runs really good when the engine is cold but as it warms up it misfires and dies. If I keep the gas pedal to the floor, it stays running but lacks power. When I let off the pedal it will die.