You dont need C-clip eliminators,or a roll bar to run 11's. You need a bar to go faster then 11.50,and C-clip eliminators to go faster then 10.99,and to be honest,with an automatic,and under 5000 stall,I doubt you will brake stock axles even running well into the 10's.
I have done some real strong low buck combos. It all depends on the condtion of what you have. If the 454 isnt tired,you can pic up some power on a budget by swapping on a set of closed chamber large oval heads from a 60's era bigblock. These heads are still fairly cheap,and usually easy to find on Ebay ect. I wouldnt spend big money or effort on them though. I would have them freshened with a good 3 angle valve job and back cut on the stock valves,fresh springs,and have them milled about .030" . This will get you over 9:1 with the engine you have(which is probably really about 7.5:1 right now). From there,go with a mild flat tappet hydraulic cam that will keep you under 6000 rpm. I have run the Isky 280 Mega cam in a few combos like this. You can run that cam with stock rockers,but a cheap set of 1.8:1 rollers like Harland Sharps is money well spent. From there,find an older single plane intake,I prefer to original design Torker(the one where the carb sits crooked),and port match it to the heads. This intake likes a 1" spacer if you have the room for it. Top it off with any double pumper you can find that 750 or large cfm,and make sure that whatever air cleaner you use as at least 1" over the top of the choke horn. Either mill the horn,or use a riser under the air cleaner and a hood scoop to get the room. You will need to track tune the carb,and might not get to your goal out of the box. A good performance HEI and low resistance wires like MSD wires is more then enough spark. Use a set of inexspensive heads,my choice is the Hooker regular competition headers for the 70-72 application. They fit 73 and later if you cut a small notch in the upper part of the 73 and later motor mounts. You will need good exhaust. Summit makes a low priced kit in 3" that they sell without mufflers,and you can then add better mufflers to that.
I would use solid body mounts,and bolt inframe connectors,then have the connectors welded to the front subframe and welded to the braces that they come close to under the floors. This is much different then real weld in connectors that require cutting a channel out of the floor and doing a lot of other work.
From there,you should run about a 3000 stall convertor,and the biggest RV/Towing trans cooler you can fit into the front of the car. A shift kit in the trans doesnt really add any signifigant performance,it is just a personal preferance. With 28" tall sticky tires and slapper bars I would run 3.42's or 3.55's,while you could run 3.90's with 30" tall tires.
This is just a ball park on what you need to get a 3600# car into the basement 12's high 11's depending on the altitude and how fresh your parts are.