670...holley truck avenger....need a lil help..

[flat black]

ok guys i have a new holley 670 truck avenger(-2 model)....i bolted it on, hooked all the lines up, adjusted the floats,fuel to air, idle etc....i never had a problem with any other carb b4...it runs awesome and idles perfect, except when its under a load it boggs down.  i changed the nozzle to a 35 instead of a 28 and its closer but not perfect, even bought the secondary spring kit and no dice, the only thing ill try yet is the pump cam kit with the diff color cams....anyone ever work on these...?  help is greatly appreciated...

[VileZambonie]

Are the secondaries opening?

[flat black]

if you go thru the gears 1-2-3 and stand on it, it hesitates and takes off like a rocket.  i changed the accel pump cam to the #2 hole and it got better..but not quite gone...i feel as if they are opening yes

[Irish_Alley]

i have the same problem with my 620 i think but if I'm not mistaking someone once mention the vacuum advace being the problem. i have a 670 also but it literally squeals like a pig thought maybe a bearing was going bad but it was just the carb sucking air somewere rebuilt it and still same problem

[TexasRed]

My holley that I rebuilt, always had this squeal to her, I thought it was the power steering pump but I believe it was the secondary linkage allowing the secondaries to be a little open. It explains why when the carb returns to idle the engine keeps racing because those secondaries are still open somewhat (and this was a spreadbore so those secondaries were HUGE). When I turned the engine off, it didn't diesel, the secondary spring would close them due to less vacuum in the engine and then I could restart the motor and it'd be fine.  Took me awhile to figure out that gem.

[flat black]

i worked on the carb yesterday, i bought the accelorator cam kit and the secondary spring kit......i changed the spring to a purple one, took out the .028 nozzle and put in a .035...then used the orange cam on setting #2  and it runs perfect...