3" Exhaust Installation

My 69 Charger R/T currently has exhaust manifolds and 2 1/2" exhaust with cut-outs and a H pipe. I have headers with 3" collectors. Would I be losing a lot of power by keeping the 2 1/2" exhaust? If I install all new exhaust, what should expect to pay an exhaust shop, not including cut-outs and mufflers? Should I have a h-pipe, x-pipe or neither? The engine is almost stock with a 272/455 cam and Performer RPM intake/770 Street Avenger carb. Thank you in advance for any insight!

I believe any restriction past the header collector flange including the "collector reducers" costs power (dragster zoomies ain't restricted) and I dont believe velocity/restriction issues past that point help power (want zero restriction). With a near stock eng you wont gain a significant amt & the headers will be the biggest gain. You want an X pipe and mandrel bends & the issue will be to get the noise back down to a tolerable level. glasspacks/resonators alongside the rear springs will let you run less restrictive (noisier) muffs up front so the overall noise level is dealable. The best plan (& cheapest ex for the cutouts) is to add the headers/keep your current 2&1/2 system rearward but plumb in 3" cutouts (either cable or elec) right at the collector flange so no reduction. this keeps it quiet normally but when the money is in the hands of a neutral third party 10 seconds later its all over but the cryin

2 1/2" with a H pipe is more than enough with a stock combo, the headers are a plus...a 3" exhaust would be in the cards for you if you had an extra 200+ HP on tap...otherwise just a loss of $$$$ and horsepower for your current configuration IMHO

Going with 3" will cost you some bottom-end & midrange performance. On a gas engine, you need to maintain a good flow velocity through the system - too large is beneficial in a diesel engine, but not a gas engine. As far as H vs. X-pipe, make your decision based on what sound you like better. One is not going to PERFORM better than the other. Use good flowing mufflers - there are certain designs that flow much better than others. If you want a stock-looking muffler that flows well - one with spun-locked heads, then I'd recommend Dynomax Super Turbos or the stainless Ultra Flos. If you don't mind using a welded assembly muffler, then you'll have a bunch to choose from. You'll get all kinds of opinions here on this board as personal preferences vary widely.