Exhaust Questions

[stevieray36]

Ready to replace the exhuast system on an 82 C-10 w/350 SB and auto transmission. The collector that came with the headers is 2.5" diameter. The current exhaust is 2" diameter. Should we run the exhaust to muffler then tail pipe in 2.5" diameter or reduce it before or after the muffler? We would like to add an "H" cross over, where is the best location closer to the headers or mufflers? What diamter pipe to use for the "H" cross over? What performance muffler is the best value? We are cost sensitive as this project has exceeded our budget.

[eventhorizon66]

I would run about a 2.25" exhaust all the way if it is a stock to mildly modified 350.  If both sides of the exhaust are equal in length, I don't think it matters where you put the H-pipe.  The most convenient place would probably be near the transmission tail housing, where it can be its shortest and the driveshaft isn't a concern.  The most common H-pipe (I've seen) is the same diameter as the rest of the system.

Also, if cost is a big issue, you could definitely save some with a single 3".  While it wont have quite the same sound, a single 3" will support plently of power (confirmed 400 NA rwhp on a late model Camaro) and most likely boost low-end torque.  Just make sure the Y-pipe is nice and smooth.

And if you are saying you want to keep as much of the current 2" system.  I would reduce it immediately after the headers (as gradually as possible), put a 2" h-pipe near the tail housing, and then simply run 2" straight-through style mufflers.  This system would probably be fine if your engine's peak hp comes in before 5000 rpm.

[Captkaos]

You say the current exhaust is 2".  Are you planning on keeping it (or some part of it)?  Or are you planning to remove everything and start over?
If you are going to keep it, you will have to reduce it down to make it work.
The H-pipe should be at least the same size and the exhaust.  To find the best location for the H-pipe typically you can put some heat sensitive tape or wax and drive it and find where the hottest point is.  Problem it usually is where it has to go under the transmission.
I typically use Dynomax mufflers.

[okuma]

simple, just run 2 1/2" from the headers  H-PIPE by tranny crossmember and install 2 flowmasters ---  use only 2 1/2" tubes all on your dual exhaust.....