Yes you can,I have one on my 65 and it just clears.I do have a torque bar going from the head to the frame so
I dont know if there will be a issue with out it.Not a 340 but a healthy 318 but should work the same.
By how much? would it possible to get a measurement from the rear air cleaner stud to the hood bars of firewall?
I do plan on a torque bar/engine strap on mine also.
Another q, does it fit under the hood?