I'm using tti shorties on my 408 stroker with an x-pipe and flowmaster 40's. 2 -1/2 " pipe front to back.
You will give up a little hp at higher rpm but if your car is mostly street driven, it wont make much of a difference.
The best thing with a 4-speed is how tight you can keep the exhaust to the floor pan. No collector scraping .
Also, love the easier access and clearance to the rest of the engine.
I have had long tubes and would never go back to them, except maybe for a track car.
Absolutely love the shorties!