I have a 1960 235 truck engine. Replacing rings on one piston. Manual for the 1960 series states "Compression rings in all truck engines are the deep section twist type. This type of compression ring takes its name from its installed position which is cocked or twisted. It assumes and maintains this position for life because the upper edge of its diameter is chamfered." In the specs section the manual states "Upper compression ring: Thickwall Inside bevel, Lower compression ring: Thickwall taper faced scraper". When checking the rings that were on the piston i see both compression rings have the inside chamfer (as alluded to in the manual). My question centers around my replacement ring set, the top compression ring has no chamfer, the bottom compression rings do. Is this going to make any difference? Since i have a complete ring set and only am replacing them on one piston i could use a bottom ring also for the top in order to obtain a top chamfered ring as well if its important? Any advice. My ring set is supposedly for a 1960 era 235 (Enginetech part # R35646) but i believe 1953 and earlier 235 rings are different, perhaps i have a pre 1953 set??? any advice?