Number one problem for off idle hesitation (assuming everything is mechanically sound and working) has to do with the idle settings. Usually, the idle transfer slot is exposed to much. It should only be exposed about .040 to .060. It can be over exposed for many reasons. But again assuming that the carb is properly selected for the motor, then my first guess would be initial timing. As a rule of thumb, the hotter the cam the more initial timing the motor will like. The more initial timing, with in reason, the more you can close down the butterflys. Check your initial and total timing and see where you are. With a 230 at .050 cam I have about 18 degress initial. Pull the carb and see how much of your transfer slot is explosed. If over or under exposed, open or close the secondary by the same number of turns you have to open or close the primary. Idealy, you will have little or no secondary transfer slot exposed. Once set up, I adjust my idle speed with the secondaries. Holley has a cheap little kit that will allow you to do this with the carb on the car. Of course if you have a very radical cam, drilling of the butterflys is the way to go. You know this is required because you can not get the car to idle with the butterflys properly set. Once you rule that out, how far is to idle mixture screws out from seated when PROPERLY adjusted? 1 to 1.5 is about perfect. Try this little trick, with the car idleing at temp, tap the accelorator pump to squirt a little gas into the motor, NOT blip the throttle. Does the idle get better, worse or stay the same? If better, the car wants more fuel, turn your screws out a bit. I think you get it from there! Forget 'lean best idle practices' with these motors, give it what it wants. More then 1 to 1.5 and you are pulling to much fuel from the transfer 'curcuit'. Less and the transfer 'curcuit' will be rich. If this is the case, then usually a modification to the idle feed restrictors/bleeds is required. Any good Holley book on modifications will guide you through the entire process. Tune with the air cleaner in place. If you can't get to the screws because of a drop base, flip the base over while you are tuning. Don't forget to flip it back over before you close the hood!
If this doesn't work... go have a couple of stiff drinks and call us in the morning!
