good idea to pull the intake. when you have it off remove the carbs. look at the throttle plates from the bottom side of the carbs and make sure that they closed all the way and are centered in the bores. get a promax base plate and jet plate. i agree with the 70 jets and 33-35 sqt.can't see how it runs with only 6* inital, would seem like the throttle plates are open,are you using a dial back timing light, if so make sure it is set at zero. when setting the idle disconnect the outboards. there is a really good post here about tuning and adj the six pack, it is a bit long but very good check the tech archives. i have it saved to my favorites maybe i could forward it to you.