have a 360 with a small cam 6 pack heads mopar intake and a holly 4150. will not stay at idle. this is the third carb I have tried and it's the same thing. it will idle at 1100 rpms for about 5 to ten seconds then it climbs to over 2000. I can hold the brake and load the clutch (4-speed)to bring it down but 5 seconds later it climbs.carb has no choke plate and I'm using a stock dist. with over 200,ooo miles. any help would be welcome

Vac leak possibly. recent onset? any part/tuning changes preceding this happening?

checked for vac leaks found none.have not changed any parts been doing this since built (years)

What is your meaning of "6 pack heads" even if they were true offset rocker heads it would not make any difference weather they were t/a heads or 318 smog heads with the problem you describe.

How many miles on the motor

Have you pulled the vac hose off the power booster and plugged it to see if it helps, a bad diaphragm in booster and even the vac can can be a hidden bug.

I would swap the disturber and if no change id re seal the intake, then if no change look at the common little gremlns.

What's the initial timing?

This just might be an issue.
Any other parts with this condition?

have not checked the power booster. don't have a vac. can. no other parts with high miles. am thinking the springs in the dist. are weak after that many miles thanks all for the input

applying vacuum advance at idle can cause a similar issue with a stock distributor.

don't have a vac advance thanks

Sounds like sticking or broken pieces in dist holding the idle up. Bet the springs are broken or rusted away

I had that on my lumpy 440 cam install

I had to add a lot of initial timing and recurve the dist with the FBO mech advance limiter plate.

I now have it locked on 0* and it is set at 36* total runs like a beast and idles 850 rpm

check to make sure the carb throttle plates are not open too far and on transition slots.

I chased a idle problem for a long time. get it idle good but when stopped on street in traffic it would be idled up a few 100 rpm and I would have to blip the throttle a couple times to get it to drop to curb idle setting.

vac pod leaked for 1 sluggish on acceleration with no vac advancing and weights/springs were dry gummed up not letting it drop back at idle.

get a new reman dist and ditch the high mileage unit.

when you say no vac can for mechanical advace does that mean you have a leanburn IGN system with a stock dist/no vac can????

or does it have one and not hooked up? add a vac source to see if it advance any?

no vac leaks found correct?

sure sounds like throttle blades on trans slots like most holleys when acting this way.

may want to check to make sure it did not get 318 intake gaskets on 360 heads/intake ports.

could have internal vac leak.

what mopar intake? spredbore or squarebore or both?

might check 4150 base gasket on intake flange for leaks