Is the H pipe for a 66/67 the same as a 68/69. Wheel base the same etc?

Looking for a 66 Cornet and vendor only has them for 68.

On wheelbase the 1966-1970 Dodge is 1" longer than Plymouth.

66-67 vs 68-70 The fuel tank is different, tailpipes are different. Are the mufflers in a slightly different position to set up the tailpipes correctly?

So is a 66/67 Dodge H pipe the same as a 68/69 Dodge? Just muffler exits different in 68/69?

I don't know, but the WB is the same. They sell the same muffler for each year.

I'm wondering if the head pipe places the muffler in a different place or angle to set up the tailpipes.

To answer your question. The replacement/after market hemi h-pipes are the same part number for 1966-70 Dodge or Plymouth. The muffler angles are not different for the 66/67 applications versus the 68-70 applications. The tailpipes are the difference for 66/67 applications as the fuel tank and gas filler tube are designed differently than the later models. In other words later 68-70 tailpipes will not fit 66-67 applications properly. As far as wheel bases are concerned, there are not two different h-pipes to accommodate the two wheel bases as there are not any fit issues for installing the h-pipe on either one.
Hope this information helps.