Exact Reproduction New Master Cylinder 1965-1966 with Power Brakes, has the 1/4" fitting.
RPO #J50. This master cylinder uses 1/4" inlet for brake line and fits 1965 Corvette built in May of 1965 to end of production 1966. Check your line size before ordering. 3/16" was used on early 1965's and 1/4" was used after April 1965