The chance that this thing has any Triumph DNA in it is very unlikely, but the seller seems to think so. In 1958 Triumph sold two models in the USA, the swoopy TR3 roadster and the aging TR10 sedan, neither of which would make a good starting point for a Lotus Seven Replica.
Per the seller:
1958 Triumph has 2.3 Ford Engine, 5 speed transmission. This is a great little car. Has new tires. Fast. Plenty of power. Runs great. I am 72 years old and don't need anymore. No trade ins. CK area.