stiffening spitfire chassis

[dandw]

hi all, just starting a spitfire chassis based kit(check out fiorano web site) looks like early alfetta 159 /ferrari 166? maserati 250f. im putting an alfa 2000 105 engine in just to keep it italian type and iknow there is going to be handling issues does any one know of any solution to triumphs wibbly wobbly ladder type chassis and strange spring affairat the rear (apart from ditching the chassis and building anew one ),which i cant really do if iwant to keep an age related plate and tax exempt? all ideas and suggestions welcomethanks dan