Cam mounted dizzy vs. block mounted

[TheTrashMan]

Hello! New here to the forum, I own a '77 with a dual points distributor and recently replaced the shaft seal (man that pin looked way easier to remove in the youtube videos!). Having a tough time finding the rotor for this style of distributor, and have done some research and found that upgrading to the electronic ignition system on the later models to be a fairly straightforward upgrade. Now, I've seen that a block-mounted distributor is readily available, and wanted to know what the advantages/disadvantages of swapping over to such a distributor would be, or if swapping over to the cam mounted electronic distributor would be a better idea. A few concerns would be:
1) Finding a plug to cover the original distributor location
2) Wiring the coil in its new location
3) Airbox fitment, I currently have the factory skillet-shaped airbox installed
4) Spark plug wire length and where to find wires that will reach (if the factory ones don't reach)
Also, on a side note, the car is equipped with the factory 32ADFA which does not have the vacuum advance to the distributor connected (if it even has one on the carb to begin with) and I would very much like to have a vacuum advance, or have one available when I inevitably swap over to a 34ADF or 32/36.

[calvinconrad]

you also will have to modify the oil dip stick on a block mounted distributor set up.

[18Fiatsandcounting]

Now, I've seen that a block-mounted distributor is readily available, and wanted to know what the advantages/disadvantages of swapping over to such a distributor would be, or if swapping over to the cam mounted electronic distributor would be a better idea.

Welcome, TrashMan! Note that the rotor for the '73 to '78 distributors is available at AutoRicambi, although it does seem rather pricey:
https://autoricambi.us/ignition-rotor-1973-78/

As for advantages of block vs. cam mounted distributors? Functionally, they are the same but there are some subtle differences, and here are the main issues as I see it:

Advantage of block mounted / disadvantage of cam mounted:
More hood clearance, especially in the taller 2L engine. Later models had bumps in the hood for this reason.
Cooler side of engine, so parts tend to last longer. Cam mounted are right over the hot exhaust manifold.

Disadvantage of block mounted / advantage of cam mounted:
Clearance issues for certain intake manifolds, especially if you have a dual carb setup.
Cam mounted have better access, so easier to work on.
Cam mounted distributor is closer to the spark plugs (only slightly).

I have a block mounted distributor in the 2L in my '69 spider with the flat hood, for exactly the clearance reason.

-Bryan