IIRC: stock sender is 1/4" NPT fittings. many aftermarket gauges are 1/8" NPT. so, as Chris (and i) did, take the stuff to the parts store and match it up, piece it together. i had to run an extension (1.5" IIRC) off the hex tube on the block to get clearance for two elec senders. then some adapters to adapt the Tee fitting for each sender, etc.
good luck.