what size tubes are ideal for a 289 with tri-y headers, 2", 2.25", 2.5", or 3"?

and what system will deliver a good deep, throaty, classic american muscle car sound?

 

If it is only mildly built or stock I would go with 2 1/4.

 

2.5 leave so room for improvement

 

+1 for 2.25". Leave that oversize hollow-sounding exhaust to the ricers and their soup can tailpipes. Motive has a nice 2.25 system with Flowmasters or turbos that uses stock (not universal) hangers.

None of this will be much improvement if you don't have the exhaust ports cleared out and matched to the Tri-Y's.

 

I would go with 2.25 for your application. Stay away from Flowmaster and chambered mufflers, a glasspack is better. Go with a straight through muffler like Dynomax Ultra Flow or Magnaflow. If you want a more mellow sound then turbo mufflers.

I don't think that 2.5 inch exhaust sounds hollow. Now with Flowmasters it does. I don't think that 2.5 is needed unless you have intake, cam, heads, etc.

 

check out the "dynomax race bullet" pretty much straight through

 

The dynomax race bullet is straight through and sounds great. Its a bit loud though.

 

If you do not plan on any future modifications then 2.25" is fine. Other wise go with the 2.50" and make sure you include an H-Pipe.

 

are the tri-y's a good choice though?

 

Yep. Very good broad band of power.