I currently found the last owner put some 2 and 1/4 dual exhaust with dynomax mufflers on my car.I am planning on supercharged big block..should I upgrade to 2 and half..the car is mostly street driven with a bit of track use..will there be much loss of power between the 2.25 and the 2.5 systems. and what about bottom end on the street..

 

If you're going with a supercharged BB even 2.5 is marginally small unless we're talking about a very mild blown 396. You're thinking using "small block logic". Put that aside. Big blocks more a LOT of air, especially with a blower!

 

Up to 300 hp 2.25" is about right, I have that now but I wish I had 2.5".............3" is good for you I bet, around 400-450+ hp...........


Thread jack: Hey Damon, you said you are into Qjets eh? Do you have an opinion on Jet's Stage 2 carbs they make for us that are supposedly tuned for the street and ready to go? I get mixed reactions, and might just have it rebuilt by a private smaller business I know is good at it...

 

80TA - for what you are planning, definitely upgrade to a dual 3" exhaust. That engine will move a lot of exhaust. If it were me I'd get the 3" system. This is what I have for my 413" small block.

Dave

 

3 or 3.5" Torque Tech or Dr. Gas X exhaust is the only way to go.

 

Yeah think the 3 inch torque tech is the one for me although wondering if I ran a 2.5 inch with dual electric cutouts close to the headers then the diameter of the system behind the headers won't matter as much right?? Wonder how ground clearance and driveshaft clearance etc will be with the 3 inch..3.5 is just too darn huge for me..

 

I have a 73 Camaro which had the 3" Torque Tech all the way including the 3" tailpipes. This is when I had a 406 in the car with Richmond 5spd and 9" rear.
Car is currently being reconfigured with full cage, minitubs, ladder bars/coilovers and I'm moving up to Dr. Gas X 3.5" with 3.5" Flowmasters then keeping the 3" tailpipes. New setup 421" AFR 220's carbed procharged & intercooled.
You want the exhaust system to be same diameter as your collectors thru the mufflers then you can drop down for the tailpipes if you want because the exhaust gases contract as they cool off while moving thru the pipes.