Weighing my options
they can all be made to be quick. slant /6 , 318, 340, 360, 383, 400, 413, 440
all can be stroked. aluminum heads. large intake/exhaust valves. large intake/exhaust ports. etc.
how much money do you want to put into it?
like crackedback said, you can just put good compression pistons in the 360 and it'll run like a 340. somewhere around 10:1
Buy pistons to raise compression on the 360 and run it, no fancy stuff required. With a good tune, mild cam, headers, intake, carb it would be capable of 12.50 or better et's in a good chassis.
if you can get a set of aluminum heads it's gonna cost you but will lessen the weight and handle the compression better without pinging.
there are some nice combos you can build.
a big block will give you gobs more power. but you use the same basic principles to build them up. find a good local machine shop that knows mopar builds, they can give you a bit of guidance.
like the 383 you could build it balls to the wall and run low 10's if your rear/chassis can handle it. some guy on moparts built one with a lightweight rotating assembly, aluminum rods custom pistons, lightened crank... he shifts it at like 7500 rpms lol and runs high 9's in a heavy car... naturally aspirated no nos.
but again it's what kind of money did he spend to do that...
find a good local engine builder they can give you options and info. save up some money, run what you got for now until the new is ready to drop in.