How much RPM drop from park to drive with stock type 340 convertor

Lots of good info, and some things for me to check, thanks to all! I'll answer some questions and provide more info. Stock 1970 AVS carb with 2 idle mixture screws and the idle screw on the shaft. Timing is at 14 in park, I'll ck it in gear as mentioned. Transfer slot is currently set at square. I'll open it up a bit and back timing down to set idle rpm and see what happens as mentioned. Mixture screws are open quite a bit, its what it wanted. I actually feel the stock jetting is lean, If I had a old strip kit I'd probably fatten it up a bit. Float level has been checked. Vacuum is 14 in park, Ill ck in gear. Idle speed in park is 975, drops to about 650 in D. I'll do some work and report back.