Take off the vacume advance line and plug the vacume port on the motor it was used for and make it a pure mechanical distributor.
Thats how i run all my cars and it works great.
Vacume canisters just mess with your timing and it sounds to me like your looking for a performance tuned engine.
Your engine builder told you to do it for a reason.#-o
Just install a set of light weight performance springs in your distributor.
Mancini racing sells them for $12.
There has been so much talk on here about this the last couple weeks and everyone is a little confused on what all this means.
It's the first thing you do to any distributor to make a world of differance.
It's one of the first things mopar performance told me to do back in the mid 90's and it's nothing new.
Do this first and don't look back.
Your timing will dance around with the heavy springs because it takes so much rpm to open open them up all the way.
They just start to open and your looking at the stock springs mess with the timing.
Loose the vacume advance and the stock distributor springs.
BUILD A SOLID AND MORE STABLE DISTRIBUTOR ,FOR MORE STABLE TIMING AND MORE HORSE POWER.
If a motor has a hesitation when put to the floor,most of the time it's not getting a big enough shot of gas from your carbs excellerator pump.
Put a 750 holley mechanical secondary 4150 on it.
Very easy to work on and is perfect for your engine.
I run a 4150 ON my 360 and even on my 318.
Yes ,a 318 with a 750 carb.
Too much carb-----no way \\ GOOD LUCK8)
p.s>Don't be scared ||| just try it.