Thanks to all you young guys, I converted a 1970 455 olds to gm tbi and put in a boat at 75 at years old. I used 89 454 parts with 7747 ecm. My problem is the engine is salt water cooled and and has to .run at 143 degrees. Any higher the salt comes out of the sea water and RAPIDLY collects in the engine. Has anyone dealt this type of issue. It runs fine at 143f. for my needs but not foe the ecm. Could the prom be be changed to see 143l as completly warmed up ? Thanks again steve