Hello,
I have a 1977 F150 4X4 with a 460 engine (L&L headers, Mallory Unitlite distributor and coil, MSD 6A ignition box, Performer intake). I was driving home and the engine coughed, but did not shut off. I pulled in the garage and shut it down. I tried to start it the next day and the carb (Holley 600 cfm) had gas coming out the top of it. The carb was on it's 3rd rebuild and I decided to replace it. I put on a Holley Avenger carb (770 cfm), and the engine will start, but when I give it gas the engine speed doesn't increase. I also replaced the plugs and wires. Could this be a vacuum leak? I've checked the lines and everything looks fine. Any ideas will be appreciated.

Thanks....JLCARR

 

it wouldn't be a vacuum leak that would be a rough idle but if you want to check that then get some starting fluid and while the truck is runnung spray around the carb and if eng. spead increases you have a vacuum leak. I would look more at your throttle linkage. When you hook up your linkage rig it for full throttle and make sure your butterflies are workin.
77' 250 390 bored out .80 over cobra cam roller rockers too much too list. full truck restore bottom up

 

I check for vacuum leaks with lighter fluid, and the engine doesn't speed up. Also, I started the engine with a remote starter (accelerator linkage unhooked) and still can get the engine speed above 2000 rpm. Can anyone give me ideas of what I should be trouble-shooting next?

Thanks...Jimmie