Have a fresh 261 strictly stock w/ Rochester 1 bbl carb in a 37 2 dr sedan. Going down the highway @ 50 it seems to hesitate or falter until I pull the choke out about 1/4, then things smooth out very nicely. I'm thinking its a jet prob. Had the carb rebuilt by a pro and he said the marks on the old jet was obliterated so he put in an .053? jet which is giving me the rough run. Had somewhat the same performance issue before I sent the carb out. Does anyone know what the jet specs are for a 261 or what works. Thanks for your response.