To clarify this question a little further. The 8221 had the follwoing differences;
Crankshaft - 6001006474 (2mm longer stroke)
Cylinder Head - 7701463479
Head gasket - 6001007451 (2.4mm to retain the compression ratio)
Rocker Adjustment Bolt - 6001007491
Turbo - 6001007448
Rebuild Kit - 7701463486 (Liners, Pistons, Rings,Pins, Seals + Gaskets)
Aluminium Roof
I also have a photocopy of a letter from Renault which satates:
ATTENSTATION
We, Regie Nationale des Usines Renault, certify, that the Renault 5 Turbo 2, type number 8220.00,
with an engne capacity of 1397cc, was temporarily replaced by a Renault 5 Turbo 2, type-number
8221.00, with an engine capacity of 1433cc, for the sole purpose of obtaining a homologation
certificate for the Renault 5 Maxi Turbo.
Those cars were manufactured between September 1984 and March 1985. All cars built since March 1985 are again the Renault 5 Turbo 2, type-number 8220.00 with an engine capacity of 1397cc.
TO WHOM IT MAY CONCERN
Paris, 24th Septemer 1985.
I hope that clears things up a little.