Geek that I am I had to check...Ian Fallon's book (which Ivar de Gier proof read and he assures me is the most accurate English language Guzzi reference) says "The ...1974...850T..as usual at that time had chrome bores" Then later on "Nigusil (replaced chrome) from 1980...used for the SP (Spada)..(and the) T4". All my books refer to Nigusil (Guzzi's patented silicone/nickel bore plating) but I'm sure mags at the time spelt it Nickasil which suits English (if not Italian - no K over there! Hence Chianti red wine, not Kianti..)
So it seems from at least 1974 (ie just after de Tomaso's take over) to 1979 Guzzis had chrome bores, then from 1980 on Nigusil/Nickasil. But there's something else I can't get a definitive answer on - the S3 was basically a sleeved down T3 (certainly same engine cases with the sump filter and a T3 camshaft) so I guess it had a chain drive to the cam (gears were used on the V7 Sport). The swan necks had gone by the S3 too, but the original owner of this bike fitted them anyway. Good man.
Lovely as the S3 is to look at (I painted a 400/4 this colourscheme in the 70s!) it was really the start of de Tomaso's cost cutting. Heavier and less powerful than the Sport, contemporary road tests struggled to get much over 110mph out of the S3, a good 10mph less than the Sport. The seller's looking for offers around £8500 which looks value when you realise only 950 were made, but really a Sport or Le Mans is worth the extra. If you've got it. Unless you already have a Sport and Le Mans, and want the set. The S3 wasn't a bad bike, it just wasn't as great as its predecessor and was up against the new Ducati 900SS and BMW R90S. But at least it kept the sporting V-twins coming out of Mandello, and with pleading from genius Lino Tonti, de Tomaso was persuaded to make amends with the Le Mans. More info in back issues of Benzina.
