There is no "1400 FIRE" to my knowledge. The 1116cc is an older, not-FIRE engine introduced with the FIAT 128 in 1969 and continued through the Uno 55/60. The same basic engine was produced in 1299cc/1301cc capacities for the Uno 70. There have also been other FIAT models with this engine, most notably the X1/9. With a different bore and stroke, it was turbocharged for the Uno Turbo. Finally it was 'modernised' slightly for the 1372cc/1580cc application (former in the Uno Mk2, both sizes in the Tipo and certain models of Punto). I think this engine is now finally out of production (1969-1995?), but surely goes down as one of the longest-lived engines (probably third behind the BMC A-series and the FIAT twin-cam!)
Your 1108cc FIRE however is a newer engine, first appearing in 1986 as the 999cc and then the 1108cc in 1989. I believe that it has been developed into 1242cc for the Punto, which comes with either an 8v or 16v cylinder head.
The actual design of the FIRE engine differs greatly in detail from the older, 'SOHC' motor even though it sounds similar on paper - there are no parts in common. For example, the camshaft on the FIRE is located in the cylinder head rather than in a separate housing bolted onto the head. The FIRE is a crossflow engine with vertical valves, the SOHC has the inlet and exhaust on the same side of the cylinder head, with wedge-shaped combustion chambers and inclined valves (very much in vogue in the 60's, before combustion temperatures came under the microscope in the interests of nitrous oxide emission reduction...)
Most notably, the FIRE engine is machined and assembled entirely by robots (Fully Integrated Robotised Engine) which tends to show in simpler fittings and fixtures. FIAT also claimed 20% fewer parts (if I remember correctly).
I rather get the impression (I could be wrong) that the FIRE is really a successor to the OHV 903cc engine used in the 850/127/Uno, and as such is designed to be a small and economical engine, where the 128's engine seemed to be destined at one point for motorsport use (128 Rally etc., particularly when the X1/9 arrived on the scene). As such I always had the feeling that the older engine was made stronger (borne out by the fact that FIAT turbocharged it) and that more high-performance parts are available, also helped by the fact that many SOHC-powered cars went to the USA where they were adapted for all sorts of racing (and no FIRE-powered model has ever been sold there).
I think we can say, without a doubt, that the FIAT 'SOHC' had awesome potential by the standards of the day. In standard form, it produced around 50bhp/litre. In 1970's competition it was pushed to almost 130bhp/litre! It was robust and able to run to amazing revs (8000RPM), with valvegear that was simple and strong, and able to run with wild camshafts, etc. without overheating, throwing rods, wearing bearings etc.
The newer FIRE engine (with 45bhp/litre in its most common form!) may do all of these things, but the world has moved on. The FIRE is a good engine, but so is just about every other engine used in a car over the last fifteen years or so. I don't think anyone has really concentrated on the FIRE engine in the same way as for the 'SOHC', though 'smokeme' springs to mind
Your best option at this point is to find a local specialist in these engines, someone who collects the useful parts off a number of models and builds engines for clubsport competition, etc. They will know about the cam-grinding also (it's likely that you can, but you'll need thicker valve shims to compensate for the reduced base circle diameter of the cam after grinding). I think our advice on the forum is going to be limited in usefullness because we don't know what's locally-available to you.
Hope the timing goes OK the second try!
-Alex