The small upper pipes feed the heater/defroster. They pick up water from the front vs the stock rear fed lines. The lower two, under the steering rack are the main radiator transfer pipes. They are 1-5/8" diameter, same as stock 289/302 Ford radiator hoses. With the additional volume and a 350 Corvette radiator I'm thinking I should have enough cooling. I will also overdrive the water pump to speed up the water flow some. The exhaust I agree might be pretty loud. The center muffler, really a resonator is from a V-8 Maserati Quattroporte. I installed small sprial augers at the inlets and outlets, some opposed baffles in each pipe and the small balance tubes between the main pipes. All this might help some but it will be interesting on fire up!