Carb boil over and hard starts

[slam59]

I read some different post regarding this issue when i did a search here and have some questions for you all. Just had a good tune up done on my wifes 77 c20 with a 454 motor. Has a 400 edelbrock carb on it. Even did a seafoam treatment on it. Runs very good, responds very well. Also had the timing done on it was 4 degrees off i was told. Passed snog test fine. heres the issue. even after this was done, after driving it a bit when i go to shut it off then restart it like 5 minutes or longer later it is very hard to start like its not getting gas. Which i assume is carb boil over cause I have a edelbrock carb and they say they have a tenedency to do that cause the bowl is at the bottom of the carb. and my 74 has an edelbrock as well and did same thing. I put a carb spacer on that one and its a ton better. i am going to do the same on this truck with the spacer. next thing is i read that placing your fuel filter away from top of engine will also help cause when its right above the motor like mine is the fuel boils and evaporates and when u go to start theres no gas close to carb so that does not help either cause it takes a bit to get to the carb and some evaporates as it enters cause of the bowl being on the bottom of the carb. where is it best to reposition the fuel filter and how far away can it be from carb? i got the paper type wix fuel filter and u can see thru the plastic the fuel boiling in it. i am thinking by puting a spacer and placing the fuel filter somewhere else will help this issue greatly.