So you want 2 go Big block...Read this first!

Do any of you know where I can Pick up a 4-speed trans for my demon? Its got a 383 in it. Also, what would the mopar 4-speed trans be called?

Best place would be craigslist. Other than that look on here. You can buy a rebuild from brewers. there is another place you can buy a new one but i don't know the name.

some things to consider with this is...

If you are using motor mounts or motor plate.

if your car has motor mounts you need...

10.5 inch bell housing. if i remember correctly my starter hit my torsion bar with an 11 inch and motor mounts. thats why I had to go 10.5)
BB Z bar kit from brewers performance or switch to hydrolic ( i prefer Z bar)
A833 4spd tranny
shifter
shifter rods
fly wheel. make sure you know if your engine is internal or ext. if it is internal, a 318 flywheel will work. But I think yours is ext. but I do not know.
clutch kit
clutch fork

If you have motor plate you will need...
10.5 inch or 11 inch bell will fit because the motor plate makes the engine sit higher in the engine bay. but I think you need fenderwell headers in order to fit the 11inch. again I could be wrong.
you will have to go hyd clutch
10.5 or 11 inch flywheel.
shifter rods
shifter
clutch fork
A833 four spd
clutch kit
and you may have to have your drive shaft shortend. but your old one should work. you may or may not be able to use the same yoke

should be about it.

Phil