Hi everyone
Dodge 360 crate engine, with M1 single plane aluminum intake, 288/292 cam duration, holley 700 cfm with mechanical sec., will not return to the same idle rpm's, vac. lines are plugged on the engine. Any info. would be helpful.
Thanks
Ensure that your throttle linkage is hanging up. When it happens disconnect the linkage and see if the idle returns to normal.
Throttle linkage is not hanging up, it does the same thing with linkage disconnected. It starts losing rpm's , vac. drops, ( maybe because of rpm loss, not sure about that) sometimes it will recover and sometimes not even when the accelerator screw is adjusted.
Maybe the needle and seats sticking in the carb or maybe float level set too low
Be sure the distributer is not loose and moving around.
Can you give a little more info regarding the engine? Is this engine new to you, a fresh build, did this combination run well prior to now?
I say carb is a tad too big in cfm. But depending on how the car will be used? It could be unfriendly for street use.
Holley carbs use a power valve if I remember? I know the vacuum signal in the plenum is everything.
could you borrow a 600 edelbrock to see if it does the same thing? Edlebrocks dont use power valves.
Also if your gonna stay with the holley? Find a friend who knows holleys
How are you setting the distributor? At idle or total (engine reved up to get full advance)? Did you try setting the idle mixture screws with a vacuum gauge?
How much vacuum do you have at idle?
As mentioned above, more information regarding your car will help to give you better answers.
Richard