Somebody help! I recently aquired a 77 stepside 400cu w/ a 4bbc holley carb sitting on top. Haven't had any problems til the other night. Driving down the freeway at about 65 and the motor started acting like it was strangled and not getting the fuel, I stopped and when it went back to idle, began working fine again. Tried to get back up to speed, started having issues again. I don't have these problems until I get to speeds around 40-45. Anyone have any ideas, I'm used to fuel injection. Thanks.

 

Hughes,

Check your fuel filter to assure it isn't clogged/blocked. It might be a good idea to just replace it if you can't remember when it was replaced.

If you have a fuel pressure gauge you could check to see that you have 7psi of fuel presure at the input of the carb. If the pressure is low replace the fuel pump.

Check the float levels on the Holley by removing the sight hole plugs (i.e. threaded plug) on the passenger's side of the bowls. When the truck is sitting level, the fuel level should be at the bottom of the sight holes. You can adjust the float level (when the engine is running) by loosening the set screw that resides on top of the hex nut (on the top of the bowl), rotating the hex nut counter-clockwise to raise the float level and clockwise to lower the float level. Once the adjustment is made tighten the set screw to fix the position. Certain years of Holley floats were a neoprene rubber which eventually saturated and fails to float, so it is possible that you will not be able to raise the float level enough to properly set the level. If so you will need to have the floats replaced. This isn't difficult but you may want to seek the help of someone with carb experience to assist.

If these procedures don't help please jump back on-line and let me know.