want to build new motor
Whats the goal for the car ET wise ? Theres no reason the stock heads cant work with some good porting. The heads may limit peak power but with the big crank and smallish head the motor will make tons of torque and have a nice loq peak on the street. May J heads were enough to make almost 500hp with a stock stroke 340 and pushed 3600lbs in to the mid 11s.
I also dont feel the the Edelbrock heads are worth upgrading to. They still have a small port and while they may flow better then a ported J head, if your going to upgrade go big like a W2 or Indy.