Correct me if I'm wrong but didn't these FE's come from the factory with manifold vacuum running to the vacuum advance like many other vehicles? Then C.A.R.B. came to be and manufacturers were mandated to hook the vacuum advance to ported vacuum?
I dont have time to research when or if ford changed the spec on which port was to be used, but this link has some scanned pictures several posts down which are for 1958 ford fe's and may be informative.
that has basicly a strait bar under the point plate,with 4 springs on it,I have never seen a distributer with an advance set up like that. The vacuum advance had what looked like 30 deg of movement,the normal advance set up was about 10,not much and sort of backwards.
So my guess is you are correct,early FE's used full manifold vacuum,load sensing timing adjustment.
The Pop Corn is for when the next 15 post tell me I'm full of it.....
Want a handful?
Some of the smog control applications have a valve that ports distributor vacuum to straight manifold vacuum at water temps above 200 degrees to increase fan speed for better cooling at stop lights. In general though you want ported vacuum for best performance.
Eric, All engines in 65-66 F100-F250's 240, 300 & 352's had a hard metal vacuum line that was threaded into the distributor vacuum advance and then a push in to carb. (thread in to carb on 240 & 300) All were "PORTED" vacuum. I have Factory Ford drawings and pics from a few different angles that show this. A couple of my trucks had the stock hard vacuum line. Probably still have at least one.
Ford put a loop~hump in hard line to allow for distributor adjustment.