340 intake questions

The early intakes with the four holes are called square bore. Thermoquads use spreadbore. The stock 340 intake is an excellent intake minus the fact that it weighs a ton.
As far as port size, you have the 273/318 size and 340/360 size. You do not want to use the smaller port intake on a 340. Im not familiar with the professional products intake? Is that the air gap clone? Edelbrock RPM Air Gaps use the larger ports.