What should I do about my exhaust?

[JON70CST]

Hey guys,

I finally got my 454 dropped into my 1970 CST/10 this past weekend, got it fired up and it runs, sounds, and looks great! The truck was a factory BBC 402 truck so that made things a LITTLE bit easier.

Now that you know a bit of the background here's my question:

The 454 I put into the truck is built up a bit with a 280H Comp Cam, roller rockers, domed pistons RPM Airgap Intake, Holley Street HP 750 carb, Flowtech longtube headers just to mention some of the important stuff. I am debating whether I should have 2.5" or 3" dual exhaust installed on the truck. Either way I am planning on going with DynoMax Welded Ultra Flo mufflers. I have been given prices of about $700 for the 2.5" and $950 for the 3". My goal is to have this thing on the street within the next 3 weeks.. as it is a big car weekend coming up here in Lethbridge (Street Machine Weekend) and I would love to be able to take the truck for a few laps around town that weekend. There are a few things left that I need to take care of before I get the insurance safety inspection done including the exhaust, hence why the price of the 2.5" would be nice, but at the same time I would much rather do it right the first time if 3" is going to be more applicable.

I have one muffler shop recommending the 2.5", saying the 3" won't truly give me that much more flow, and another shop strongly suggesting the 3"

What do I do?!?!? and sorry for the novel of an explanation.

CHEERS!