I have a 383 blueprint engine (420 hp/450 tq} it has a TH350 trans with a 2600 - 2700 stall convertor , pertronix vacuum advance dist. the timing is where blueprint suggests (32 to 34 deg. total @ 3500 rpm ) I have to idle it at about 1350 rpm , so when I put it in gear it drops to about 900 rpm (it drops an additional 200 rpm when the dual electric fans come on . What can I do to lessen this rpm drop ?