New to the forum and seeking advice. I have a 55 Ranch Wagon project car. After removing the motor and checking, bearings within tolerance, cylinders look good and heads also good. New standard bearings and rings, hone and reassemble. Set timing, confirm spark and fuel but no start. I discovered low compression. 60psi all cyl. Disassemble and found ring gap of .025 all cylinders. Now the questions. The installed rings were old stock Continental standard size. I am reading that newer rings may be larger for better fit and may require filing. I believe the ring gap to be the problem because I could see slight blow by at the oil cap during cranking. I am looking at new rings so new standard size or oversize? I believe the correct ring gap is .008-.020, so is there a formula to figure the correct ring size?