I'm going to be fitting a bigger carb to my 1275 soon (still runs 1098 stuff) but can't afford to replace the exhaust system.

When I had a Midget engine it was helped by using the Mini 1 1/2" manifold and using the exhaust part of that as it flows better and still lets you use the standard exhaust.How do you find it runs with a big carb and inlet but only a small outlet?