Good thread guys with great information coming out.
The car I refer to is a FIAT 124 special T saloon with an engine capacity of 1592cc which would allow the use of the 1756cc twincam engine based on the 12.5% rule. The thoughts we have at the moment are to fit a FIAT 131 transmission (1975-83) and a Mazda diff. The brakes both front and rear would be FIAT but larger vented rotors at the front and larger rotor at the rear with calipers from FIATs of the late 1980s or early 90s. We would use 14 inch wheels (13 inch was standard). We are looking to build something that is reliable and safe that we could use for a variety of events without spending a huge fortune. We've already done that to achieve one good Targa finish in our FIAT 131R.
As an aside and not to highjack this thread Targa have a weird rule (my personal opinion) that places the car in a class/category according the last year of production which I find unusual as the way I see it the technology that built the car is normally 10 years or so before that.
Allan