rough idle

[lorny]

vacuum is 18 , car starts ok , drves ok but idles rough at stop signs
i do not have history on car , has 600 cfm edelbrock everything else looks stock including seesed heat riser plugs are burning a nice chocolate brown

 

[diesel_lv]

Timing, AFR, idle RPM, or vacuum leak. Just some possibilities. You mentioned plugs, so I'm not bringing up misfire.

 

[Photon440]

Not knowing the history, perhaps someone put in a different cam when they installed the 4bbl? How is the engine at higher speeds? Are you talking about your '66?

 

[R413]

Check the valve adjustment. Often overlooked, Poly and 1964-67 273 they are solid lifters and need proper adjustment.

 

[lorny]

yes 66 the chrome air breather has a decal wich looks mopar saying 318 POLY 325 HP
was there ever a 318 putting out that much power
decal looks mopar not home made
i'm hoping its a cam and not a flat lobe
under the orange paint there's a lot af grey
another tell tale the 3 spd trans works great and shifts hard
i think original open hwy diff (caked on 50 yrs greese dirt ) frame under engine also caked with greese . engine and trany fairly clean

 

[PRND21]

Check your basics, timing, dwell, compression, valve clearance. Start narrowing it down.

 

[mountain33]

I just had similar issues with my 383. Did all the basics, checked plugs ,point, cap, rpm, carb adjustments and timing. I found my timing was off. When i loosened distributor and grabbed to adjust timing. I got nailed by bad wire. Runs great now.