Originally Posted by my87Z
i have a 87 camaro that has the typical y-pipe and cat-back exhaust and that is fine for the wimpy 305 4brl in it now but i have a 385ci that i will be putting in it sooner than later, ive heard some say a Y-pipe into a 3"cat back system (without the cat), but i just can t see running this, a Y-PIPE
i just cant do it, and most all shops in my area wont mess with a custom (illegal) exhaust, even if paid to with no paper work, so i know i want long tube headers, and round mufflers, here is what i have come up with so far
in a nut shell headman elite long tube headers w/3" collector, 12" collector extensions, 3"- 2.5" reducer, 12x4" moroso 2.5 in/out round tube mufflers, and then just a set of turndowns
what do you think of this exhaust system
Do you have to qualify for smog any more?
If not, true duals, as you propose, would be the way to go with or without cats. Add a crossover pipe, it lets each side share the other, that is really helpful for flow. Doesn't so much matter whether an H or X pipe, just that it's there.
Be careful of ending the pipes anywhere besides under and slightly behind the rear bumper. There is a low pressure area that is always behind the forward moving car, it gets bigger with more speed and smaller with less. It is useful to use as a scavenge technique as it puts the tail pipes under a bit of suction. Dumping anyplace else requires knowing the airflow in that area, it's possible with side or under dumps to actually have a local air flow trying to pressurize the end of the pipes restricting their flow instead of helping it.