The ones I wanted to upgrade to are no longer available....Looking for 3" muffler ideas that I can uncork at the track quickly for drag week...

Flowtech Warlock Bypass Series Mufflers 50560FLT were what I was going to buy......too late.
https://proshop.summitracing.com/parts/big-50560flt

Had to do a 3.5"system on my Duster race car many years ago for a 91 Db rule @ Sears Point.
Used Race Bullets, X-pipe, and turndowns ahead of rear axle that were angled pointed slightly inward, and had no problems.
Still a bit loud, but I could have driven it on the street that way.
"Loud" is of course subjective, but I could hear gravel against the floor on the return road w/o a helmet, if that helps describe it.

I use Marmin flanges and clamps on my exhaust. 1 bolt on the clamps. Can be removed and installed in seconds.

I bought and used a set of the early crimp steel stock type construction style Magna Flow 14 inch long oval x7.0 tall x 22 inches long overall (I think CRS) with 3.0 inch side inlets with straight through perforated 3.0 inch pipe exiting in the center. I was using a set of either Hooker 2.0 inch fenderwell headers for a BB in my Duster or maybe by then I had bought and switch to a set BB Hedman fender well headers with 2.0x3.5 inch collector . The muffs were mounted behind the rear end housing between the rear sub frame rails and the 1/4 panels with the short muff tailpipes exiting at the rear bumper, not real loud at part throttle cruise and not hurting the performance, that car would pick up from a 7.01 with them on to a 6.98 /6.99 .002 MPH gain with them completely removed from the car
I wasn't able to buy a set of 3.5 inch crimp Magna Flow muffs and tail pipes back then
IHTHs

How about electric cut outs?

If you plan on removing the exhaust at the track, why not just run 2.5" exhaust, and keep it quiet for the drives? That is what Joel runs on his Coupe, and tailpipes all the way to the rear. We could easily talk in the car, while going down the road, and Joel normally couldn't hear a dump truck driving through a nitroglycerin plant. Joel runs V band clamps, and the hangers are on simple rubber hanger. It was my job to remove, and install the exhaust at the track, and could have it completed in under 5 minutes, one way or another.

I use a DynoMax UltraFlow 3". At 600HP my car doesn't go any faster with the cutouts open. It is a pretty reasonable noise level at cruise speeds in the 3000-3500RPM range.

At this point, I am not sure which engine the Cuda will have in it this summer. I have to pull the 512/400 from the Duster for a looksy and make sure all is good, like I usually do, although I think I have like 5 passes on it in total. And the Hemi may have to come out of the Cuda to update the car for full cage, not sure. Gonna work that out with AJ I think...

So I could mild up the cam in the 512/400 and put it in the Cuda and save the big 605 Hemi from all the abuse and see if I could even make Drag Week happen. Which is the way I am leaning at the moment. Not sure how fast the car would go with a mild 512 in it, probably only 10's.....But I would need headers, preferably Hookers...Either way, I would think 2.5 " is way too small. I have run as big as 3.5" turn downs and bullet mufflers...Those were way too loud. I can handle my current mufflers for local cruising, not sure how they are on long drives.

I have been slowly checking items off my Drag Week to do list since 2019 if you can believe that, and the cage is the big one. Everything else is done or already in process except new 315 drag radials and the rims. The wiring is in process, and I have new rims I am going to use for more appropriate 31x16 street tires.

So I don't know, maybe a set of simple Y-dumps off my current necked down 3" would be enough to not kill too much ET.....

A 3.5" system w/ a pair of good straight through mufflers like Dynomax Ultraflows or Hooker Max Flows would be pretty quiet and not kill much if any ET.

I have an H pipe system for my cuda w/ a pair of 4" Hooker Max Flow mufflers and turn downs at the rear axle. I actually don't like it b/c it's a lot quieter than I expected it to be.

Mine are 3-1/2" with straight through Dynomax Ultraflows. However, not much for conversations until you get to the next destination....

One of the exhaust tests at LACR I did years ago surprised me as that car ran faster and quicker with open headers than it did with a set of short 3.5 Dyno Max bullets bolted directly to the Hooker 3.5 inch collectors

You can make enough power to go down the road on the drives through a single 1 and 1/2-inch exhaust pipe. And you can build a very quiet system with two or two and 1/2 inch mufflers and pipes. So if you're going to take the exhaust system off at the track anyway, why suffer the noise going down the road for hours on end. Look at Mike Finnegan, bless his heart. He takes off his track exhaust and puts on his Street exhaust, and it's still so loud that him and his trunk monkey where headsets with noise suppressing mics just so they can talk to each other when they're 2 ft apart. Why? I built mine quiet because I don't need 600 horsepower to drive 80 mph down the freeway. With all of the discomforts of a drag and drive event, it's nice to eliminate one of them and have a quiet exhaust and be able to have a civil conversation with your trunk monkey.

Besides, your hearing is like sandpaper, it eventually wears out.
And you one only get one set, and your grandkids will appreciate it if you take care of yours.
Says the guy who raced stub open exhaust 2 cycle go karts as a kid and worked 5 decades of rock concerts.