I have a 68 Mustang with a later model 351W engine recently rebuilt. The engine ran fine, all of a sudden it wouldn't start unless I give it some pedal, it runs extremely rough like its only running off 4 cylinders, when I release the pedal it dies. It is getting spark and fuel.

1. I recently welded on the the frame to replace floor pans, would this affect the Mallory Electronic Ignition?
2. Could it be running too rich or lean?
3. It has a edelbrock 650 carb and edelbrock intake, not sure if its dual plane or not. The fuel filter is clean but could the fuel pump not be supplying enough fuel.

Any suggestion would be appreciated.

Thanks in advance,

Eric

 

clean your carb, run high test gas, maybe some gum out....it sounds like fuel for sure. new plugs if you dont have them, something along those lines

 

yea the guy i bought it from said i needed to run higher octane fuel in it. i put 89 in it and it probably needs 93 with the higher compression, thats probably what is going on. should i drain the tank and replace all the fuel or just add octane booster? what does an engine normally do if i did indeed us too low of an octane fuel?

thanks,

 

Lower octane won't cause the problems you're describing.

If you didn't disconnect the ignition box before welding on the car, there is a good chance you damaged it.

First thing to check would be to make sure there isn't anything in your carb blocking fuel flow. A piece of gasket can easily cause the problems you're describing.

 

You ain't gona' believe this; yet you probably will. You know what they say its always the easiest solution. I drained the tank, put 93 octane in it, changed the spark plugs, and PRESTO it runs like a champ. It was just strange to me that "she" quite running all of a sudden... Anyway thanks for all you guys help. It's a awsome feeling knowing that there a people out there who can offer great advice and bounce ideas off of!

Thanks again, until next time,