depends on which megasquirt you have
old needed something like a FORD EDIS set up 36-1 wheel on crank an EDIS 8 Module 2x 4 tower coil packs off a 90s fiesta 1 condenser off fiesta
and the crank trigger out of its bellhousing (36-1 pattern in back of flywheel) ( its a long back tube with a coil and magnet in)
because the trigger wheel was on the crank this meant the system knew where the crank was in degrees of rotation and hence know what each cylinder is doing... it could calulate where TDC was for No.1, better for ignition and gives you options on the Fuel injection routine batch up NOW and NEXT cylinders or have 1 bank then the other or just fire all injectors all the same time
and you could run a wasted spark coil pack or coil on plug if you could fathom the wireing to make them look like coil pack.
i think more modern megasquirt has coil drivers built in and potentially doesn't need the EDIS module but still needs to know crank position
this means you need either
crank trigger
cam angle sensor
a distributor with a special pickup and trigger in it that marks TDC so that again the software can work out what cylinder is doing what
the most accurate measure of crank position is always the crank trigger wheel method
cam sensor and distributor both driven off the crank so their position is subject to variance built into their drive i.e slop in timing chain or wear and harmonics impacting the oil pump/dissy drive
i must admit i have not looked at megasquirt for 10+ years
and to keep things simple i think this is a better bet these days
this is a basic ECU for about £200 from Powemods in south africa
https://powermods.co.za/Pages/Shop.asp? ... PID=142207
its a clone of the GOTECH MFI-X which costs the same is made by the same geezers but is obsolete. powermods as a brand just carries on production of the obsolete Gotech stuff, gotech being the premium brand
both will allow you to use your standard dizzy (locked or ELB) with an adaptor or a range of crank trigger wheel styles
both will work in close loop self learning mode up to 25% on the throttle position sensor (all you need)
NOW they might be rubbish.... i have not got one or know anyone with one but the south africans like a fast car and like a bit of racing and they seem to like this stuff. and they are cheap because the south African Rand is worth diddley squat
nobody over here sells or fits them
manual for both is on the site listed
if i get a bonus this year i'm gonna buy one some 360 magnum injectors and some dcoe throttle bodies off sherryberg on aliexpress.com
coupled with v8 range rover in tank pump or a bosch external one
it may be a bad move, or genius i just don't want to spend £700 on an ECU £600 on injectors and £1200 quid on Jenvey dcoe heritage bodies
i am a true TAVO as the aussies would say a TightArseValiantOwner.
I've rambled
if you can find out what Megasquirt you have and which options are enabled by the software loaded on it , that will probably dictate the best ignition set up for you... chryslers have a lot of stuff on the front of the balancer already and there is a bloody big fan to account for as well so fitting more down the front of the motor like a trigger wheel and pickup can be hard work if you have aircon and power steering
and sometime the style of ignition set up you choose dictates or limits the range of options you have for firing the injectors
more options with coil on plug and wasted spark as both need a TDC indicator provided by cam or crank sensor.
sorry a lot of crap from someone who has planned it many times but never done it
Dave
They are Ford injectors that I've not managed to identify yet, even after removing the red paint on them 
