How about dropping a TR motor (4 cylinder) and making an early 'Vitesse' type car. Plus appropriate other mods to make it safe. Probably been done already but would be fun.
Eastern shore of Te Whanganui-a-Tara
Vitesse 6 (owned since 1982, driven for 6 months a long time ago) Vitesse Mk11 Conv (owned since 1992, never driven but the first Vitesse I looked at buying back in early 1982) 2000 BMW R1150 GS 2003 FFRR TD6 HSE