1971 Demon 340 TTI Exhaust System Question

So, I’m in the process of installing a 2 1/2 inch TTI complete H pipe exhaust system from the manifolds back on my 71 Demon 340 4 speed car, it has the 68 - 70 HP manifolds on it. The instructions say that about 2” may need to be cut off of the outlets of the front head pipes on some applications, I think mine might be one that needs to be cut as the pipes seem too long, it also looks to me to be too wide at the “H” to fit the head pipes, my question is, has anyone done this installation with this setup before? I don’t mind shortening the down pipes, but since the instructions mentioned nothing about cutting the “H” crossover pipe I’m not sure whether to do it or if I’m missing something here?