Chevrolet Repair: Engine running temperature, chevy blazer, chevy 1500

Question
I have a 92 71 Chevy blazer full-size with the 5.7 engine what temperature should the engine run at  I put 195 thermostat and it would make it run 210 I'v tried 185 thermostat and it would Run around a hundred degrees if I leave it running about 100° will that make the fuel efficiency go down or up or will it mess with my transmission and make it not shift right or would it bother anything else I've also had a Chevy 1500 pickup truck with a 5.7 engine and it did the exact same thing and I had to try like five different thermostats to get it to run at the proper temperature at like 185 190

Answer
HI DAVID,WHAT IS A 92 71 BLAZER ???? PUTTING A 195 STAT SHOULD LET THE ENG RUN AROUND THAT DEGREE IF ALL ELSE IS OK SUCH AS RADIATOR AND BLOCK LIKE NO CONTAMINATION IN EITHER...GAS MI WILL FALL OFF IF IT DOES NOT RACH CLOSED LOOP, LIKE 190 DEGREE.SOUNDS LIKE YOU ARE OK..GET BACK TO ME WITH MORE INFO. TOM...