Feel like it’s time to perform the next upgrade or two to my ‘72 Charger this Winter. Looking for thoughts.

Options:
1. Torq Storm style super charger
2. Turbo charger (could the space in front of the radiator core support be utilized?)
3. From 3.55 gears to 3.91 (rear end now is a narrowed 8.25 with rear drum brakes)
4. Rear disc brake conversion (not sure if this can be done to an 8.25
5. FiTech fuel injection (currently Mr. Gasket electric fuel pump)

Engine is 9.5:1, 5.9 Magnum, full roller, carbureted with a Quick Fuel
Trans is a fairly new 5 speed Tremec
Pro touring style look
Has A/C (upgraded Sanden short compressor), PS, PB
It is a street car. I bought it 11 years ago in its factory 318, AT, bench seat anemic state. I have been slowly working on giving it performance and attitude.

supercharger gets my vote

Others here are more qualified to answer, but I don't think an 8.25 rear will be happy with a small block and boost. It would probably fail rather soon. My vote would be an 8.75 rear end, and then a little boost. The torqstorm blowers are well made and would be a good addition if your 360 is built to handle the additional stress that a supercharger will place on it.

+1 on the 8-3/4.

Get a 8.75 rear end

Not on your list but a 4" crank (if you were to go back into the eng which I assume you would if you are boosting it). That'd get ya 408 cubes

Right on. I forgot about that option. It’s a good one. A couple of years ago it got nudged out by the Tremec.

I’m not surprised about the 8.75 recommendations. This is my first 8.25 so no experience breaking one. I must say this one has held up well under the 350 hp 360.

Whether a 408 or a power adder how much can the 8.25 handle? Not a glamorous swap but maybe a necessary one. Being able to ditch the drum brakes would help the looks and up the track performance.

I appreciate the input. I’m listening.

Easy to add rear discs to an 8.25. First generation Jeep Libertys are I believe the preferred donors. Rear will take up to 400 hp with a quality carrier. Me personally I'd go for EFI and rear discs. If that's not enough HP then I'd go 6.1/6.4 hemi. You probably have too much comp for much of a blower.

1 and 2 really depend on your budget, skills and goals. Turbo is the best upgrade for power but I would not go that unless 700 or more horsepower is the goal.

3. Nobody can answer this without knowing your goals and rear tire size and gearing of your Tremec 5 speed. I would recommend an 8 3/4 or Dana 60.

4. You mention Pro Touring. Then discs are a must. Drum are for stock type restorations with no desire to improve braking.

5. FI Tech is definately an upgrade from a carburetor but it is the bottom of the barrel for fuel injection. Consider something that will control fuel and ignition.

If your planning on replacing the 8 1/4, goo idea , step on up to a Dana 60 with 35 spline street axles
My suggestion is based on you wanting to add a power adder now and knowing how good increased power feels it wouldn't surprise me that you will want to add more power later
You know you will
Buy the good rear end now, now later

The manual transmission will make life more difficult for the differential. The 8-1/4" rear is pretty good after you upgrade the axles. It is not as strong as the other diffs but you'll be fine until you add a noticeable amount of power.

The FiTech is a good system but it does not like forced induction if that is in your future.

Carbs can be fussy with forced induction. Speaking from experience here.

This winter I would go with a good quality EFI system. Get something that is compatible with forced induction. Once you do that you can drop on a supercharger and tune at a later date.

I really like my turbos but they can be quite the ordeal to install.

Here is the deal if a rear end swap is done.

1. I had the current 8.25 narrowed by 2.25” on each side in order to tuck the 12” tires under it, maintain the offset and get a deep dish on the design side of the wheel. So most likely I am looking at a custom width on any size housing.
2. With the 5 speed trans the rear gear needs to go to a 3.91. This will help the 5.9 rev quicker to its power band.
3. As stated in a reply the drums need to go and discs brought in.
4. The assembly would need to be reliable up to 450 hp when I eventually get it there. Hard street driving and an occasional pass or two on the strip or auto cross. No need for it to have to hold full on racing power.

Now the question would be:
With me having very limited experience in working with assemblies and diffs, do I just let someone build this thing from the chunk to the brakes, gather up the parts and build it up myself or do something in between. I don’t have unlimited financial resources but I don’t like cheap junk either.

The biggest concern for me doing this myself is narrowing the housing correctly.

I believe I've seen quite a few forced induction FiTech setups, what do you feel they fall short on when it comes to that? Personally, I'd go with the Sniper, however.

https://fitechefi.com/products/30004/

I agree that they are the bottom of the barrel, but they do manage both fuel and timing. While it still relies on a dizzy, I'm not sure the average joe needs much more than push button timing control.

I have an 8 1/4 in my 470" BB A-body 4spd(425 rwhp). Running a cone sure grip and 3:73 gears. It's been flawless. However I only run 245 BFGs. The tires are the fuse, they don't hook at all. If you plan on sticky tires and making passes the 8 3/4 or Dana should be your plan.

I've spent a ton of money on a lot of 8 3/4 trying to make them live with sticky tires, a TON
The manual trans will break the driver side carrier cap which will kill the other parts, I've seen a bunch of 8 3/4 ring gears with the outer side of the teeth cracked with motors making less than 500 HP with slicks at the drag strip, I had one tooth corner break off and go through the pinion and ring gear, tore that rear end up.
As far as you building or buying a complete rear end do you have a shop that can narrow a housing that you trust? If so junk yard Dana 60 pickup and van read ends may be a good option for you, some of the Ford F150 pickups from the mid 1980 to mid 1990 came with a Dana 60 with conventional 5 lug wheels and brakes so if you could find one of those it would be a good choice to narrow and reuse in your car.
One thing you need to know is Dana Corp made a bunch of different Dana 60 for the cars, vans and pickup, the axle tubes can be from 2.5 O.D. to 3.1/4 O.D. so be choosy on what you buy so it will work well with your U bolts and spring retainer plates
Dana 60 never came with a 3.90 gear, 3.54, 3.73, 4.10 and up to 5.57 stock, maybe even 6.17 in some of the Air Force 3/4 ton four door Dodge crew cab flight line 6 cylinder pick ups
Dana 60 came with 17, 23, 30 and 35 spine axles stock also.
IHTHs

Well, there I go again making another blanket statement....

At the time I was looking at them there was not a forced induction offering. They're solid budget systems but I'd like to go with something that allows more flexibility because of the crazy stuff I get into. Using something like the Sniper is a bit better in that regard because there are others out there familiar with tuning them. Support from other users is not far away.

I follow both of the popular FiTech and Sniper facebook groups, the problems seem to be pretty similar between them, more times than not, it's user-error. Holley at least has some online support presence and their support seems to be a bit better. That said, we haven't had any issues with the FiTech that is installed on Li'l Red. Their user interface/handheld is quite a piece of junk, however.

When the time comes, I will buy a Sniper for the Warlock. For what I use it for, it will be more than fine, honestly 90% of the people out there will probably be just fine. For those that want to tweak endlessly and get into the guts of how it operates, there are much better options out there for that.