Granted the mufflers are different. And, the 75 has alot of plumbing. But, is it the actual heat exchangers that bold onto the motor that cause the loss of power in the 75, or is it just the muffler system? Hypothetical - If you mounted a 73 banana muffler on both (which u cant), how much decrease in HP would the 75 have do to the exchangers?

Thanks

The 75s go forward and do a 180 then come back....they use a different mounting flange and have a cat pipe in front of the muffler.

ah ok mike. I just noticed also, there is only a pair of single tubes that connect to the muffler. The earlier i noticed have a pair of double tubes. I guess they siamese it on the 75.

Yup....they will fit on any 914 motor...IF you use everything....you can't swap parts for different years.

The only difference between the 73 and 75 exhausts is...

you dont want the 75 if you have the choice. Thats all anyone needs to know.