I want to mount a Grundfos UPS15-58F pump. The centerline measurement for the bolts is 3 and 5/32 inches with round holes. Which flange should I use, "The Isolator" flange 50404 which has a round bolt centerline of 3 and 3/16 inches, or rather the 50404HV, which has an oblong bolt centerline of 3 and 1/2 inches.
The oblong bolt holes on the 5040HV look like they have some play while the round bolt holes on the 5040 (at 3 and 3/16 inches) don't look like they have any play.
The specs for the flanges are at www.webstonevalves.com/pdfs/Iso_4pg_silver_final_tscreen.pdf
Would the Taco 00R-MSF1-IFC be as good or better than the Grundfos?
Would any other flanges be as good or better choice?
Thanks for any help.