I wonder how much of a gain I will get!

My 440 dart I picked up seemed a little flat on bottom,it pulled ok but not a big tire roasting monster, I start checking it over yesterday and find that there is absolutely no timing advance, there must be a hole in the vacume diaphram because you can draw strait through it with a mightyvac tool plus the whole advance plate inside the distributer is siezed up,I couldnt even move it with a screwdriver,got a new distributer on the way:thumblef:hopefully I will see a performance gain!
Wow wow holy sheeeite this thing is a bear now,popped in a electronic conversion deal,mopar performance looks like a stock electronic dist,now it will roast the rubber until I decide to stop,all through first and all through second feather off into 3rd and it starts to go!!!!I was a bit dissapointed at first with this car,my last car was a 67 chevelle with a LS-7 454 I figured the dart would be as quick but with the bad dist it wasn't even close,now I would say they are really close!