I own a yellow 1980 alfasud, 2 door. Your project is good though if I may can I suggest you keep the original engine but do some inner modifications, such as lightening up and balancing flywheel, crank and pulley. Also what I had done was port the cylinder heads for higher flow and upgraded the dell'orto carburators by replacing with main jets and four in one exhaust system. Lastly I got hold of a 1986 33 and replaced the gearbox and front and rear suspension so as to have outboard discs. Who ever owned a sud knows the nightmare of the leaking inner caliper problems especially the hand brake, wow so many memories lol ! I must mention I changed the differential from the 4:1 to 4:4 ratio. To be honest these cars are very scarce nowadays due to their rust infection but they were build to race and if you got hold of a good conditioned one keep her as such, believe me it will be worth much more and btw with these modifications you get tremendous acceleration and stability. I still manage to overtake my brothers' fiat 130 Abarth which should not be underestimated ! I had done these modifications 14 years ago roughly, so back then parts were still readily available, I guess today its a different story. In any case good luck and let us know !