I'm running a Robin Hood Project 2b with a 1600 Pinto engine, it's got a standard carb on it and to be honest is running a bit flat... What's my best option to replace the carb to get maximum performance?

Sounds like an ad for the Atkin's diet !

Welcome to the forum.
If by standard carb you mean the VV one then try and get a webber manifold and carb.
But idealy bike carbs.
Steve.