Rear exhaust vs under car exhaust

[dcdoug]

Originally Posted by mickmate

The undercar exhaust on originals with the cast iron restrictive exhaust manifolds loses about 100HP. If you use tubular tri Y headers with 2" primaries and good mufflers you'll only marginally affect performance. I have made them for originals and newer cars and they look and work good.

Don't you lose about the same with side pipes anyway (assuming you aren't running straight pipes). I was under the impression that because under car exhaust allows for more efficient header design, that you can actually achieve more power with under car exhaust that side pipes.